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http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Neko | Neko | /* command line arguments, neko */
var argc = $asize($loader.args)
/* Display count and arguments, indexed from 0, no script name included */
$print("There are ", argc, " arguments\n")
var arg = 0
while arg < argc $print($loader.args[arg ++= 1], "\n") |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #Elena | Elena | //single line comment
/*multiple line
comment*/ |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #Elixir | Elixir |
# single line comment
|
http://rosettacode.org/wiki/Conway%27s_Game_of_Life | Conway's Game of Life | The Game of Life is a cellular automaton devised by the British mathematician John Horton Conway in 1970. It is the best-known example of a cellular automaton.
Conway's game of life is described here:
A cell C is represented by a 1 when alive, or 0 when dead, in an m-by-m (or m×m) square array of cells.
We calculate N - the sum of live cells in C's eight-location neighbourhood, then cell C is alive or dead in the next generation based on the following table:
C N new C
1 0,1 -> 0 # Lonely
1 4,5,6,7,8 -> 0 # Overcrowded
1 2,3 -> 1 # Lives
0 3 -> 1 # It takes three to give birth!
0 0,1,2,4,5,6,7,8 -> 0 # Barren
Assume cells beyond the boundary are always dead.
The "game" is actually a zero-player game, meaning that its evolution is determined by its initial state, needing no input from human players. One interacts with the Game of Life by creating an initial configuration and observing how it evolves.
Task
Although you should test your implementation on more complex examples such as the glider in a larger universe, show the action of the blinker (three adjoining cells in a row all alive), over three generations, in a 3 by 3 grid.
References
Its creator John Conway, explains the game of life. Video from numberphile on youtube.
John Conway Inventing Game of Life - Numberphile video.
Related task
Langton's ant - another well known cellular automaton.
| #Julia | Julia | julia> Pkg.add("CellularAutomata")
INFO: Installing CellularAutomata v0.1.2
INFO: Package database updated
julia> using CellularAutomata
julia> gameOfLife{T<:Int}(n::T, m::T, gen::T) = CA2d([3], [2,3], int(randbool(n, m)), gen)
gameOfLife (generic function with 1 method)
julia> gameOfLife(15, 30, 5)
30x15x5 Cellular Automaton |
http://rosettacode.org/wiki/Conditional_structures | Conditional structures | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
List the conditional structures offered by a programming language. See Wikipedia: conditionals for descriptions.
Common conditional structures include if-then-else and switch.
Less common are arithmetic if, ternary operator and Hash-based conditionals.
Arithmetic if allows tight control over computed gotos, which optimizers have a hard time to figure out.
| #Dragon | Dragon | if(a == b)
{
add()
}
else if(a == c)
less() //{}'s optional for one-liners
else
{
both()
} |
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #Raku | Raku | [eq] @strings # All equal
[lt] @strings # Strictly ascending |
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #Red | Red | Red []
list1: ["asdf" "Asdf" "asdf"]
list2: ["asdf" "bsdf" "asdf"]
list3: ["asdf" "asdf" "asdf"]
all-equal?: func [list][ 1 = length? unique/case list ]
sorted?: func [list][ list == sort/case copy list ] ;; sort without copy would modify list !
print all-equal? list1
print sorted? list1
print all-equal? list2
print sorted? list2
print all-equal? list3
print sorted? list3
|
http://rosettacode.org/wiki/Comma_quibbling | Comma quibbling | Comma quibbling is a task originally set by Eric Lippert in his blog.
Task
Write a function to generate a string output which is the concatenation of input words from a list/sequence where:
An input of no words produces the output string of just the two brace characters "{}".
An input of just one word, e.g. ["ABC"], produces the output string of the word inside the two braces, e.g. "{ABC}".
An input of two words, e.g. ["ABC", "DEF"], produces the output string of the two words inside the two braces with the words separated by the string " and ", e.g. "{ABC and DEF}".
An input of three or more words, e.g. ["ABC", "DEF", "G", "H"], produces the output string of all but the last word separated by ", " with the last word separated by " and " and all within braces; e.g. "{ABC, DEF, G and H}".
Test your function with the following series of inputs showing your output here on this page:
[] # (No input words).
["ABC"]
["ABC", "DEF"]
["ABC", "DEF", "G", "H"]
Note: Assume words are non-empty strings of uppercase characters for this task.
| #Lasso | Lasso | #!/usr/bin/lasso9
local(collection =
array(
array,
array("ABC"),
array("ABC", "DEF"),
array("ABC", "DEF", "G", "H")
)
)
with words in #collection do {
if(#words -> size > 1) => {
local(last = #words -> last)
#words -> removelast
stdoutnl('{' + #words -> join(', ') + ' and ' + #last'}')
else(#words -> size == 1)
stdoutnl('{' + #words -> first + '}')
else
stdoutnl('{}')
}
} |
http://rosettacode.org/wiki/Comma_quibbling | Comma quibbling | Comma quibbling is a task originally set by Eric Lippert in his blog.
Task
Write a function to generate a string output which is the concatenation of input words from a list/sequence where:
An input of no words produces the output string of just the two brace characters "{}".
An input of just one word, e.g. ["ABC"], produces the output string of the word inside the two braces, e.g. "{ABC}".
An input of two words, e.g. ["ABC", "DEF"], produces the output string of the two words inside the two braces with the words separated by the string " and ", e.g. "{ABC and DEF}".
An input of three or more words, e.g. ["ABC", "DEF", "G", "H"], produces the output string of all but the last word separated by ", " with the last word separated by " and " and all within braces; e.g. "{ABC, DEF, G and H}".
Test your function with the following series of inputs showing your output here on this page:
[] # (No input words).
["ABC"]
["ABC", "DEF"]
["ABC", "DEF", "G", "H"]
Note: Assume words are non-empty strings of uppercase characters for this task.
| #Liberty_BASIC | Liberty BASIC |
do
read in$
if in$ ="END" then wait
w =wordCount( in$)
select case w
case 0
o$ ="{}"
case 1
o$ ="{" +in$ +"}"
case 2
o$ ="{" +word$( in$, 1) +" and " +word$( in$, 2) +"}"
case else
o$ ="{"
o$ =o$ +word$( in$, 1)
for k =2 to w -1
o$ =o$ +", " +word$( in$, k)
next k
o$ =o$ +" and " +word$( in$, w) +"}"
end select
if w =1 then
print "'"; in$; "'"; " held "; w; " word. "; tab( 30); o$
else
print "'"; in$; "'"; " held "; w; " words. "; tab( 30); o$
end if
loop until 0
wait
function wordCount( IN$)
wordCount =1
for i =1 to len( IN$)
if mid$( IN$, i, 1) =" " then wordCount =wordCount +1
next i
end function
end
data "" 'No input words.
data "ABC" 'One input word.
data "ABC DEF" 'Two words.
data "ABC DEF G" 'Three words.
data "ABC DEF G H" 'Four words.
data "END" 'Sentinel for EOD.
|
http://rosettacode.org/wiki/Combinations_with_repetitions | Combinations with repetitions | The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of those sets is chosen from
S
{\displaystyle S}
.
In the real world, it is about choosing sets where there is a “large” supply of each type of element and where the order of choice does not matter.
For example:
Q: How many ways can a person choose two doughnuts from a store selling three types of doughnut: iced, jam, and plain? (i.e.,
S
{\displaystyle S}
is
{
i
c
e
d
,
j
a
m
,
p
l
a
i
n
}
{\displaystyle \{\mathrm {iced} ,\mathrm {jam} ,\mathrm {plain} \}}
,
|
S
|
=
3
{\displaystyle |S|=3}
, and
k
=
2
{\displaystyle k=2}
.)
A: 6: {iced, iced}; {iced, jam}; {iced, plain}; {jam, jam}; {jam, plain}; {plain, plain}.
Note that both the order of items within a pair, and the order of the pairs given in the answer is not significant; the pairs represent multisets.
Also note that doughnut can also be spelled donut.
Task
Write a function/program/routine/.. to generate all the combinations with repetitions of
n
{\displaystyle n}
types of things taken
k
{\displaystyle k}
at a time and use it to show an answer to the doughnut example above.
For extra credit, use the function to compute and show just the number of ways of choosing three doughnuts from a choice of ten types of doughnut. Do not show the individual choices for this part.
References
k-combination with repetitions
See also
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #R | R | library(gtools)
combinations(3, 2, c("iced", "jam", "plain"), set = FALSE, repeats.allowed = TRUE)
nrow(combinations(10, 3, repeats.allowed = TRUE)) |
http://rosettacode.org/wiki/Combinations_with_repetitions | Combinations with repetitions | The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of those sets is chosen from
S
{\displaystyle S}
.
In the real world, it is about choosing sets where there is a “large” supply of each type of element and where the order of choice does not matter.
For example:
Q: How many ways can a person choose two doughnuts from a store selling three types of doughnut: iced, jam, and plain? (i.e.,
S
{\displaystyle S}
is
{
i
c
e
d
,
j
a
m
,
p
l
a
i
n
}
{\displaystyle \{\mathrm {iced} ,\mathrm {jam} ,\mathrm {plain} \}}
,
|
S
|
=
3
{\displaystyle |S|=3}
, and
k
=
2
{\displaystyle k=2}
.)
A: 6: {iced, iced}; {iced, jam}; {iced, plain}; {jam, jam}; {jam, plain}; {plain, plain}.
Note that both the order of items within a pair, and the order of the pairs given in the answer is not significant; the pairs represent multisets.
Also note that doughnut can also be spelled donut.
Task
Write a function/program/routine/.. to generate all the combinations with repetitions of
n
{\displaystyle n}
types of things taken
k
{\displaystyle k}
at a time and use it to show an answer to the doughnut example above.
For extra credit, use the function to compute and show just the number of ways of choosing three doughnuts from a choice of ten types of doughnut. Do not show the individual choices for this part.
References
k-combination with repetitions
See also
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #Racket | Racket |
#lang racket
(define (combinations xs k)
(cond [(= k 0) '(())]
[(empty? xs) '()]
[(append (combinations (rest xs) k)
(map (λ(x) (cons (first xs) x))
(combinations xs (- k 1))))]))
|
http://rosettacode.org/wiki/Compiler/lexical_analyzer | Compiler/lexical analyzer | Definition from Wikipedia:
Lexical analysis is the process of converting a sequence of characters (such as in a computer program or web page) into a sequence of tokens (strings with an identified "meaning"). A program that performs lexical analysis may be called a lexer, tokenizer, or scanner (though "scanner" is also used to refer to the first stage of a lexer).
Task[edit]
Create a lexical analyzer for the simple programming language specified below. The
program should read input from a file and/or stdin, and write output to a file and/or
stdout. If the language being used has a lexer module/library/class, it would be great
if two versions of the solution are provided: One without the lexer module, and one with.
Input Specification
The simple programming language to be analyzed is more or less a subset of C. It supports the following tokens:
Operators
Name
Common name
Character sequence
Op_multiply
multiply
*
Op_divide
divide
/
Op_mod
mod
%
Op_add
plus
+
Op_subtract
minus
-
Op_negate
unary minus
-
Op_less
less than
<
Op_lessequal
less than or equal
<=
Op_greater
greater than
>
Op_greaterequal
greater than or equal
>=
Op_equal
equal
==
Op_notequal
not equal
!=
Op_not
unary not
!
Op_assign
assignment
=
Op_and
logical and
&&
Op_or
logical or
¦¦
The - token should always be interpreted as Op_subtract by the lexer. Turning some Op_subtract into Op_negate will be the job of the syntax analyzer, which is not part of this task.
Symbols
Name
Common name
Character
LeftParen
left parenthesis
(
RightParen
right parenthesis
)
LeftBrace
left brace
{
RightBrace
right brace
}
Semicolon
semi-colon
;
Comma
comma
,
Keywords
Name
Character sequence
Keyword_if
if
Keyword_else
else
Keyword_while
while
Keyword_print
print
Keyword_putc
putc
Identifiers and literals
These differ from the the previous tokens, in that each occurrence of them has a value associated with it.
Name
Common name
Format description
Format regex
Value
Identifier
identifier
one or more letter/number/underscore characters, but not starting with a number
[_a-zA-Z][_a-zA-Z0-9]*
as is
Integer
integer literal
one or more digits
[0-9]+
as is, interpreted as a number
Integer
char literal
exactly one character (anything except newline or single quote) or one of the allowed escape sequences, enclosed by single quotes
'([^'\n]|\\n|\\\\)'
the ASCII code point number of the character, e.g. 65 for 'A' and 10 for '\n'
String
string literal
zero or more characters (anything except newline or double quote), enclosed by double quotes
"[^"\n]*"
the characters without the double quotes and with escape sequences converted
For char and string literals, the \n escape sequence is supported to represent a new-line character.
For char and string literals, to represent a backslash, use \\.
No other special sequences are supported. This means that:
Char literals cannot represent a single quote character (value 39).
String literals cannot represent strings containing double quote characters.
Zero-width tokens
Name
Location
End_of_input
when the end of the input stream is reached
White space
Zero or more whitespace characters, or comments enclosed in /* ... */, are allowed between any two tokens, with the exceptions noted below.
"Longest token matching" is used to resolve conflicts (e.g., in order to match <= as a single token rather than the two tokens < and =).
Whitespace is required between two tokens that have an alphanumeric character or underscore at the edge.
This means: keywords, identifiers, and integer literals.
e.g. ifprint is recognized as an identifier, instead of the keywords if and print.
e.g. 42fred is invalid, and neither recognized as a number nor an identifier.
Whitespace is not allowed inside of tokens (except for chars and strings where they are part of the value).
e.g. & & is invalid, and not interpreted as the && operator.
For example, the following two program fragments are equivalent, and should produce the same token stream except for the line and column positions:
if ( p /* meaning n is prime */ ) {
print ( n , " " ) ;
count = count + 1 ; /* number of primes found so far */
}
if(p){print(n," ");count=count+1;}
Complete list of token names
End_of_input Op_multiply Op_divide Op_mod Op_add Op_subtract
Op_negate Op_not Op_less Op_lessequal Op_greater Op_greaterequal
Op_equal Op_notequal Op_assign Op_and Op_or Keyword_if
Keyword_else Keyword_while Keyword_print Keyword_putc LeftParen RightParen
LeftBrace RightBrace Semicolon Comma Identifier Integer
String
Output Format
The program output should be a sequence of lines, each consisting of the following whitespace-separated fields:
the line number where the token starts
the column number where the token starts
the token name
the token value (only for Identifier, Integer, and String tokens)
the number of spaces between fields is up to you. Neatly aligned is nice, but not a requirement.
This task is intended to be used as part of a pipeline, with the other compiler tasks - for example:
lex < hello.t | parse | gen | vm
Or possibly:
lex hello.t lex.out
parse lex.out parse.out
gen parse.out gen.out
vm gen.out
This implies that the output of this task (the lexical analyzer) should be suitable as input to any of the Syntax Analyzer task programs.
Diagnostics
The following error conditions should be caught:
Error
Example
Empty character constant
''
Unknown escape sequence.
\r
Multi-character constant.
'xx'
End-of-file in comment. Closing comment characters not found.
End-of-file while scanning string literal. Closing string character not found.
End-of-line while scanning string literal. Closing string character not found before end-of-line.
Unrecognized character.
|
Invalid number. Starts like a number, but ends in non-numeric characters.
123abc
Test Cases
Input
Output
Test Case 1:
/*
Hello world
*/
print("Hello, World!\n");
4 1 Keyword_print
4 6 LeftParen
4 7 String "Hello, World!\n"
4 24 RightParen
4 25 Semicolon
5 1 End_of_input
Test Case 2:
/*
Show Ident and Integers
*/
phoenix_number = 142857;
print(phoenix_number, "\n");
4 1 Identifier phoenix_number
4 16 Op_assign
4 18 Integer 142857
4 24 Semicolon
5 1 Keyword_print
5 6 LeftParen
5 7 Identifier phoenix_number
5 21 Comma
5 23 String "\n"
5 27 RightParen
5 28 Semicolon
6 1 End_of_input
Test Case 3:
/*
All lexical tokens - not syntactically correct, but that will
have to wait until syntax analysis
*/
/* Print */ print /* Sub */ -
/* Putc */ putc /* Lss */ <
/* If */ if /* Gtr */ >
/* Else */ else /* Leq */ <=
/* While */ while /* Geq */ >=
/* Lbrace */ { /* Eq */ ==
/* Rbrace */ } /* Neq */ !=
/* Lparen */ ( /* And */ &&
/* Rparen */ ) /* Or */ ||
/* Uminus */ - /* Semi */ ;
/* Not */ ! /* Comma */ ,
/* Mul */ * /* Assign */ =
/* Div */ / /* Integer */ 42
/* Mod */ % /* String */ "String literal"
/* Add */ + /* Ident */ variable_name
/* character literal */ '\n'
/* character literal */ '\\'
/* character literal */ ' '
5 16 Keyword_print
5 40 Op_subtract
6 16 Keyword_putc
6 40 Op_less
7 16 Keyword_if
7 40 Op_greater
8 16 Keyword_else
8 40 Op_lessequal
9 16 Keyword_while
9 40 Op_greaterequal
10 16 LeftBrace
10 40 Op_equal
11 16 RightBrace
11 40 Op_notequal
12 16 LeftParen
12 40 Op_and
13 16 RightParen
13 40 Op_or
14 16 Op_subtract
14 40 Semicolon
15 16 Op_not
15 40 Comma
16 16 Op_multiply
16 40 Op_assign
17 16 Op_divide
17 40 Integer 42
18 16 Op_mod
18 40 String "String literal"
19 16 Op_add
19 40 Identifier variable_name
20 26 Integer 10
21 26 Integer 92
22 26 Integer 32
23 1 End_of_input
Test Case 4:
/*** test printing, embedded \n and comments with lots of '*' ***/
print(42);
print("\nHello World\nGood Bye\nok\n");
print("Print a slash n - \\n.\n");
2 1 Keyword_print
2 6 LeftParen
2 7 Integer 42
2 9 RightParen
2 10 Semicolon
3 1 Keyword_print
3 6 LeftParen
3 7 String "\nHello World\nGood Bye\nok\n"
3 38 RightParen
3 39 Semicolon
4 1 Keyword_print
4 6 LeftParen
4 7 String "Print a slash n - \\n.\n"
4 33 RightParen
4 34 Semicolon
5 1 End_of_input
Additional examples
Your solution should pass all the test cases above and the additional tests found Here.
Reference
The C and Python versions can be considered reference implementations.
Related Tasks
Syntax Analyzer task
Code Generator task
Virtual Machine Interpreter task
AST Interpreter task
| #QB64 | QB64 | dim shared source as string, the_ch as string, tok as string, toktyp as string
dim shared line_n as integer, col_n as integer, text_p as integer, err_line as integer, err_col as integer, errors as integer
declare function isalnum&(s as string)
declare function isalpha&(s as string)
declare function isdigit&(s as string)
declare sub divide_or_comment
declare sub error_exit(line_n as integer, col_n as integer, msg as string)
declare sub follow(c as string, typ2 as string, typ1 as string)
declare sub nextch
declare sub nexttok
declare sub read_char_lit
declare sub read_ident
declare sub read_number
declare sub read_string
const c_integer = "Integer", c_ident = "Identifier", c_string = "String"
dim out_fn as string, out_tok as string
if command$(1) = "" then print "Expecting a filename": end
open command$(1) for binary as #1
source = space$(lof(1))
get #1, 1, source
close #1
out_fn = command$(2): if out_fn <> "" then open out_fn for output as #1
line_n = 1: col_n = 0: text_p = 1: the_ch = " "
do
call nexttok
select case toktyp
case c_integer, c_ident, c_string: out_tok = tok
case else: out_tok = ""
end select
if out_fn = "" then
print err_line, err_col, toktyp, out_tok
else
print #1, err_line, err_col, toktyp, out_tok
end if
loop until errors or tok = ""
if out_fn <> "" then close #1
end
' get next tok, toktyp
sub nexttok
toktyp = ""
restart: err_line = line_n: err_col = col_n: tok = the_ch
select case the_ch
case " ", chr$(9), chr$(10): call nextch: goto restart
case "/": call divide_or_comment: if tok = "" then goto restart
case "%": call nextch: toktyp = "Op_mod"
case "(": call nextch: toktyp = "LeftParen"
case ")": call nextch: toktyp = "RightParen"
case "*": call nextch: toktyp = "Op_multiply"
case "+": call nextch: toktyp = "Op_add"
case ",": call nextch: toktyp = "Comma"
case "-": call nextch: toktyp = "Op_subtract"
case ";": call nextch: toktyp = "Semicolon"
case "{": call nextch: toktyp = "LeftBrace"
case "}": call nextch: toktyp = "RightBrace"
case "&": call follow("&", "Op_and", "")
case "|": call follow("|", "Op_or", "")
case "!": call follow("=", "Op_notequal", "Op_not")
case "<": call follow("=", "Op_lessequal", "Op_less")
case "=": call follow("=", "Op_equal", "Op_assign")
case ">": call follow("=", "Op_greaterequal", "Op_greater")
case chr$(34): call read_string
case chr$(39): call read_char_lit
case "": toktyp = "End_of_input"
case else
if isdigit&(the_ch) then
call read_number
elseif isalpha&(the_ch) then
call read_ident
else
call nextch
end if
end select
end sub
sub follow(c as string, if_both as string, if_one as string)
call nextch
if the_ch = c then
tok = tok + the_ch
call nextch
toktyp = if_both
else
if if_one = "" then call error_exit(line_n, col_n, "Expecting " + c): exit sub
toktyp = if_one
end if
end sub
sub read_string
toktyp = c_string
call nextch
do
tok = tok + the_ch
select case the_ch
case chr$(10): call error_exit(line_n, col_n, "EOL in string"): exit sub
case "": call error_exit(line_n, col_n, "EOF in string"): exit sub
case chr$(34): call nextch: exit sub
case else: call nextch
end select
loop
end sub
sub read_char_lit
toktyp = c_integer
call nextch
if the_ch = chr$(39) then
call error_exit(err_line, err_col, "Empty character constant"): exit sub
end if
if the_ch = "\" then
call nextch
if the_ch = "n" then
tok = "10"
elseif the_ch = "\" then
tok = "92"
else
call error_exit(line_n, col_n, "Unknown escape sequence:" + the_ch): exit sub
end if
else
tok = ltrim$(str$(asc(the_ch)))
end if
call nextch
if the_ch <> chr$(39) then
call error_exit(line_n, col_n, "Multi-character constant"): exit sub
end if
call nextch
end sub
sub divide_or_comment
call nextch
if the_ch <> "*" then
toktyp = "Op_divide"
else ' skip comments
tok = ""
call nextch
do
if the_ch = "*" then
call nextch
if the_ch = "/" then
call nextch
exit sub
end if
elseif the_ch = "" then
call error_exit(line_n, col_n, "EOF in comment"): exit sub
else
call nextch
end if
loop
end if
end sub
sub read_ident
do
call nextch
if not isalnum&(the_ch) then exit do
tok = tok + the_ch
loop
select case tok
case "else": toktyp = "keyword_else"
case "if": toktyp = "keyword_if"
case "print": toktyp = "keyword_print"
case "putc":: toktyp = "keyword_putc"
case "while": toktyp = "keyword_while"
case else: toktyp = c_ident
end select
end sub
sub read_number
toktyp = c_integer
do
call nextch
if not isdigit&(the_ch) then exit do
tok = tok + the_ch
loop
if isalpha&(the_ch) then
call error_exit(err_line, err_col, "Bogus number: " + tok + the_ch): exit sub
end if
end sub
function isalpha&(s as string)
dim c as string
c = left$(s, 1)
isalpha& = c <> "" and instr("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_", c) > 0
end function
function isdigit&(s as string)
dim c as string
c = left$(s, 1)
isdigit& = c <> "" and instr("0123456789", c) > 0
end function
function isalnum&(s as string)
dim c as string
c = left$(s, 1)
isalnum& = c <> "" and instr("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_", c) > 0
end function
' get next char - fold cr/lf into just lf
sub nextch
the_ch = ""
col_n = col_n + 1
if text_p > len(source) then exit sub
the_ch = mid$(source, text_p, 1)
text_p = text_p + 1
if the_ch = chr$(13) then
the_ch = chr$(10)
if text_p <= len(source) then
if mid$(source, text_p, 1) = chr$(10) then
text_p = text_p + 1
end if
end if
end if
if the_ch = chr$(10) then
line_n = line_n + 1
col_n = 0
end if
end sub
sub error_exit(line_n as integer, col_n as integer, msg as string)
errors = -1
print line_n, col_n, msg
end
end sub
|
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Nemerle | Nemerle | using System;
using System.Console;
module CLArgs
{
Main(args : array[string]) : void
{
foreach (arg in args) Write($"$arg "); // using the array passed to Main(), everything after the program name
Write("\n");
def cl_args = Environment.GetCommandLineArgs(); // also gets program name
foreach (cl_arg in cl_args) Write($"$cl_arg ");
}
} |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #NetRexx | NetRexx | /* NetRexx */
-- sample arguments: -c "alpha beta" -h "gamma"
say "program arguments:" arg
|
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Nim | Nim | import os
echo "program name: ", getAppFilename()
echo "Arguments:"
for arg in commandLineParams():
echo arg |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #Elm | Elm |
-- a single line comment
{- a multiline comment
{- can be nested -}
-}
|
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #Emacs_Lisp | Emacs Lisp | ; This is a comment |
http://rosettacode.org/wiki/Conway%27s_Game_of_Life | Conway's Game of Life | The Game of Life is a cellular automaton devised by the British mathematician John Horton Conway in 1970. It is the best-known example of a cellular automaton.
Conway's game of life is described here:
A cell C is represented by a 1 when alive, or 0 when dead, in an m-by-m (or m×m) square array of cells.
We calculate N - the sum of live cells in C's eight-location neighbourhood, then cell C is alive or dead in the next generation based on the following table:
C N new C
1 0,1 -> 0 # Lonely
1 4,5,6,7,8 -> 0 # Overcrowded
1 2,3 -> 1 # Lives
0 3 -> 1 # It takes three to give birth!
0 0,1,2,4,5,6,7,8 -> 0 # Barren
Assume cells beyond the boundary are always dead.
The "game" is actually a zero-player game, meaning that its evolution is determined by its initial state, needing no input from human players. One interacts with the Game of Life by creating an initial configuration and observing how it evolves.
Task
Although you should test your implementation on more complex examples such as the glider in a larger universe, show the action of the blinker (three adjoining cells in a row all alive), over three generations, in a 3 by 3 grid.
References
Its creator John Conway, explains the game of life. Video from numberphile on youtube.
John Conway Inventing Game of Life - Numberphile video.
Related task
Langton's ant - another well known cellular automaton.
| #Kotlin | Kotlin | // version 1.2.0
import java.util.Random
val rand = Random(0) // using a seed to produce same output on each run
enum class Pattern { BLINKER, GLIDER, RANDOM }
class Field(val w: Int, val h: Int) {
val s = List(h) { BooleanArray(w) }
operator fun set(x: Int, y: Int, b: Boolean) {
s[y][x] = b
}
fun next(x: Int, y: Int): Boolean {
var on = 0
for (i in -1..1) {
for (j in -1..1) {
if (state(x + i, y + j) && !(j == 0 && i == 0)) on++
}
}
return on == 3 || (on == 2 && state(x, y))
}
fun state(x: Int, y: Int): Boolean {
if ((x !in 0 until w) || (y !in 0 until h)) return false
return s[y][x]
}
}
class Life(val pattern: Pattern) {
val w: Int
val h: Int
var a: Field
var b: Field
init {
when (pattern) {
Pattern.BLINKER -> {
w = 3
h = 3
a = Field(w, h)
b = Field(w, h)
a[0, 1] = true
a[1, 1] = true
a[2, 1] = true
}
Pattern.GLIDER -> {
w = 4
h = 4
a = Field(w, h)
b = Field(w, h)
a[1, 0] = true
a[2, 1] = true
for (i in 0..2) a[i, 2] = true
}
Pattern.RANDOM -> {
w = 80
h = 15
a = Field(w, h)
b = Field(w, h)
for (i in 0 until w * h / 2) {
a[rand.nextInt(w), rand.nextInt(h)] = true
}
}
}
}
fun step() {
for (y in 0 until h) {
for (x in 0 until w) {
b[x, y] = a.next(x, y)
}
}
val t = a
a = b
b = t
}
override fun toString(): String {
val sb = StringBuilder()
for (y in 0 until h) {
for (x in 0 until w) {
val c = if (a.state(x, y)) '#' else '.'
sb.append(c)
}
sb.append('\n')
}
return sb.toString()
}
}
fun main(args: Array<String>) {
val lives = listOf(
Triple(Life(Pattern.BLINKER), 3, "BLINKER"),
Triple(Life(Pattern.GLIDER), 4, "GLIDER"),
Triple(Life(Pattern.RANDOM), 100, "RANDOM")
)
for ((game, gens, title) in lives) {
println("$title:\n")
repeat(gens + 1) {
println("Generation: $it\n$game")
Thread.sleep(30)
game.step()
}
println()
}
} |
http://rosettacode.org/wiki/Conditional_structures | Conditional structures | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
List the conditional structures offered by a programming language. See Wikipedia: conditionals for descriptions.
Common conditional structures include if-then-else and switch.
Less common are arithmetic if, ternary operator and Hash-based conditionals.
Arithmetic if allows tight control over computed gotos, which optimizers have a hard time to figure out.
| #DWScript | DWScript | if a:
pass
elseif b:
pass
else: # c, maybe?
pass |
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #REXX | REXX | /* REXX ---------------------------------------------------------------
* 28.06.2014 Walter Pachl
*--------------------------------------------------------------------*/
Call mklist 'ABC','AA','BB','CC'
Call test 'ABC'
Call mklist 'AAA','AA','AA','AA'
Call mklist 'ACB','AA','CC','BB'
Call test 'AAA'
Call test 'ACB'
Exit
mklist:
list=arg(1)
do i=1 by 1 To arg()-1
call value list'.'i,arg(i+1)
End
Call value list'.0',i-1
Return
test:
Parse Arg list
all_equal=1
increasing=1
Do i=1 To value(list'.0')-1 While all_equal | increasing
i1=i+1
Select
When value(list'.i1')==value(list'.i') Then increasing=0
When value(list'.i1')<<value(list'.i') Then Do
all_equal=0
increasing=0
End
When value(list'.i1')>>value(list'.i') Then all_equal=0
End
End
Select
When all_equal Then
Say 'List' value(list)': all elements are equal'
When increasing Then
Say 'List' value(list)': elements are in increasing order'
Otherwise
Say 'List' value(list)': neither equal nor in increasing order'
End
Return |
http://rosettacode.org/wiki/Comma_quibbling | Comma quibbling | Comma quibbling is a task originally set by Eric Lippert in his blog.
Task
Write a function to generate a string output which is the concatenation of input words from a list/sequence where:
An input of no words produces the output string of just the two brace characters "{}".
An input of just one word, e.g. ["ABC"], produces the output string of the word inside the two braces, e.g. "{ABC}".
An input of two words, e.g. ["ABC", "DEF"], produces the output string of the two words inside the two braces with the words separated by the string " and ", e.g. "{ABC and DEF}".
An input of three or more words, e.g. ["ABC", "DEF", "G", "H"], produces the output string of all but the last word separated by ", " with the last word separated by " and " and all within braces; e.g. "{ABC, DEF, G and H}".
Test your function with the following series of inputs showing your output here on this page:
[] # (No input words).
["ABC"]
["ABC", "DEF"]
["ABC", "DEF", "G", "H"]
Note: Assume words are non-empty strings of uppercase characters for this task.
| #Logo | Logo | to join :delimiter :list [:result []]
output cond [
[ [empty? :list] :result ]
[ [empty? :result] (join :delimiter butfirst :list first :list) ]
[ else (join :delimiter butfirst :list
(word :result :delimiter first :list)) ]
]
end
to quibble :list
local "length
make "length count :list
make "text (
ifelse [:length <= 2] [
(join "\ and\ :list)
] [
(join "\ and\ (sentence join ",\ butlast :list last :list))
])
output ifelse [empty? :text] "\{\} [(word "\{ :text "\})]
end
foreach [ [] [ABC] [ABC DEF] [ABC DEF G H] ] [
print quibble ?
]
bye |
http://rosettacode.org/wiki/Comma_quibbling | Comma quibbling | Comma quibbling is a task originally set by Eric Lippert in his blog.
Task
Write a function to generate a string output which is the concatenation of input words from a list/sequence where:
An input of no words produces the output string of just the two brace characters "{}".
An input of just one word, e.g. ["ABC"], produces the output string of the word inside the two braces, e.g. "{ABC}".
An input of two words, e.g. ["ABC", "DEF"], produces the output string of the two words inside the two braces with the words separated by the string " and ", e.g. "{ABC and DEF}".
An input of three or more words, e.g. ["ABC", "DEF", "G", "H"], produces the output string of all but the last word separated by ", " with the last word separated by " and " and all within braces; e.g. "{ABC, DEF, G and H}".
Test your function with the following series of inputs showing your output here on this page:
[] # (No input words).
["ABC"]
["ABC", "DEF"]
["ABC", "DEF", "G", "H"]
Note: Assume words are non-empty strings of uppercase characters for this task.
| #Lua | Lua | function quibble (strTab)
local outString, join = "{"
for strNum = 1, #strTab do
if strNum == #strTab then
join = ""
elseif strNum == #strTab - 1 then
join = " and "
else
join = ", "
end
outString = outString .. strTab[strNum] .. join
end
return outString .. '}'
end
local testCases = {
{},
{"ABC"},
{"ABC", "DEF"},
{"ABC", "DEF", "G", "H"}
}
for _, input in pairs(testCases) do print(quibble(input)) end |
http://rosettacode.org/wiki/Combinations_with_repetitions | Combinations with repetitions | The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of those sets is chosen from
S
{\displaystyle S}
.
In the real world, it is about choosing sets where there is a “large” supply of each type of element and where the order of choice does not matter.
For example:
Q: How many ways can a person choose two doughnuts from a store selling three types of doughnut: iced, jam, and plain? (i.e.,
S
{\displaystyle S}
is
{
i
c
e
d
,
j
a
m
,
p
l
a
i
n
}
{\displaystyle \{\mathrm {iced} ,\mathrm {jam} ,\mathrm {plain} \}}
,
|
S
|
=
3
{\displaystyle |S|=3}
, and
k
=
2
{\displaystyle k=2}
.)
A: 6: {iced, iced}; {iced, jam}; {iced, plain}; {jam, jam}; {jam, plain}; {plain, plain}.
Note that both the order of items within a pair, and the order of the pairs given in the answer is not significant; the pairs represent multisets.
Also note that doughnut can also be spelled donut.
Task
Write a function/program/routine/.. to generate all the combinations with repetitions of
n
{\displaystyle n}
types of things taken
k
{\displaystyle k}
at a time and use it to show an answer to the doughnut example above.
For extra credit, use the function to compute and show just the number of ways of choosing three doughnuts from a choice of ten types of doughnut. Do not show the individual choices for this part.
References
k-combination with repetitions
See also
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #Raku | Raku | my @S = <iced jam plain>;
my $k = 2;
.put for [X](@S xx $k).unique(as => *.sort.cache, with => &[eqv]) |
http://rosettacode.org/wiki/Combinations_with_repetitions | Combinations with repetitions | The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of those sets is chosen from
S
{\displaystyle S}
.
In the real world, it is about choosing sets where there is a “large” supply of each type of element and where the order of choice does not matter.
For example:
Q: How many ways can a person choose two doughnuts from a store selling three types of doughnut: iced, jam, and plain? (i.e.,
S
{\displaystyle S}
is
{
i
c
e
d
,
j
a
m
,
p
l
a
i
n
}
{\displaystyle \{\mathrm {iced} ,\mathrm {jam} ,\mathrm {plain} \}}
,
|
S
|
=
3
{\displaystyle |S|=3}
, and
k
=
2
{\displaystyle k=2}
.)
A: 6: {iced, iced}; {iced, jam}; {iced, plain}; {jam, jam}; {jam, plain}; {plain, plain}.
Note that both the order of items within a pair, and the order of the pairs given in the answer is not significant; the pairs represent multisets.
Also note that doughnut can also be spelled donut.
Task
Write a function/program/routine/.. to generate all the combinations with repetitions of
n
{\displaystyle n}
types of things taken
k
{\displaystyle k}
at a time and use it to show an answer to the doughnut example above.
For extra credit, use the function to compute and show just the number of ways of choosing three doughnuts from a choice of ten types of doughnut. Do not show the individual choices for this part.
References
k-combination with repetitions
See also
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #REXX | REXX | /*REXX pgm displays combination sets with repetitions for X things taken Y at a time*/
call RcombN 3, 2, 'iced jam plain' /*The 1st part of Rosetta Code task. */
call RcombN -10, 3, 'Iced jam plain' /* " 2nd " " " " " */
exit /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
RcombN: procedure; parse arg x,y,syms; tell= x>0; x=abs(x); z=x+1 /*X>0? Show combo*/
say copies('─',15) x "doughnut selection taken" y 'at a time:' /*display title. */
do i=1 for words(syms); $.i=word(syms, i) /*assign symbols.*/
end /*i*/
@.=1 /*assign default.*/
do #=1; if tell then call show /*display combos?*/
@[email protected] + 1; if @.y==z then if .(y-1) then leave /* ◄─── recursive*/
end /*#*/
say copies('═',15) # "combinations."; say; say /*display answer.*/
return
/*──────────────────────────────────────────────────────────────────────────────────────*/
.: procedure expose @. y z; parse arg ?; if ?==0 then return 1; p=@.? +1
if p==z then return .(? -1); do j=? to y; @.j=p; end /*j*/; return 0
/*──────────────────────────────────────────────────────────────────────────────────────*/
show: L=; do c=1 for y; [email protected]; L=L $._; end /*c*/; say L; return |
http://rosettacode.org/wiki/Compiler/lexical_analyzer | Compiler/lexical analyzer | Definition from Wikipedia:
Lexical analysis is the process of converting a sequence of characters (such as in a computer program or web page) into a sequence of tokens (strings with an identified "meaning"). A program that performs lexical analysis may be called a lexer, tokenizer, or scanner (though "scanner" is also used to refer to the first stage of a lexer).
Task[edit]
Create a lexical analyzer for the simple programming language specified below. The
program should read input from a file and/or stdin, and write output to a file and/or
stdout. If the language being used has a lexer module/library/class, it would be great
if two versions of the solution are provided: One without the lexer module, and one with.
Input Specification
The simple programming language to be analyzed is more or less a subset of C. It supports the following tokens:
Operators
Name
Common name
Character sequence
Op_multiply
multiply
*
Op_divide
divide
/
Op_mod
mod
%
Op_add
plus
+
Op_subtract
minus
-
Op_negate
unary minus
-
Op_less
less than
<
Op_lessequal
less than or equal
<=
Op_greater
greater than
>
Op_greaterequal
greater than or equal
>=
Op_equal
equal
==
Op_notequal
not equal
!=
Op_not
unary not
!
Op_assign
assignment
=
Op_and
logical and
&&
Op_or
logical or
¦¦
The - token should always be interpreted as Op_subtract by the lexer. Turning some Op_subtract into Op_negate will be the job of the syntax analyzer, which is not part of this task.
Symbols
Name
Common name
Character
LeftParen
left parenthesis
(
RightParen
right parenthesis
)
LeftBrace
left brace
{
RightBrace
right brace
}
Semicolon
semi-colon
;
Comma
comma
,
Keywords
Name
Character sequence
Keyword_if
if
Keyword_else
else
Keyword_while
while
Keyword_print
print
Keyword_putc
putc
Identifiers and literals
These differ from the the previous tokens, in that each occurrence of them has a value associated with it.
Name
Common name
Format description
Format regex
Value
Identifier
identifier
one or more letter/number/underscore characters, but not starting with a number
[_a-zA-Z][_a-zA-Z0-9]*
as is
Integer
integer literal
one or more digits
[0-9]+
as is, interpreted as a number
Integer
char literal
exactly one character (anything except newline or single quote) or one of the allowed escape sequences, enclosed by single quotes
'([^'\n]|\\n|\\\\)'
the ASCII code point number of the character, e.g. 65 for 'A' and 10 for '\n'
String
string literal
zero or more characters (anything except newline or double quote), enclosed by double quotes
"[^"\n]*"
the characters without the double quotes and with escape sequences converted
For char and string literals, the \n escape sequence is supported to represent a new-line character.
For char and string literals, to represent a backslash, use \\.
No other special sequences are supported. This means that:
Char literals cannot represent a single quote character (value 39).
String literals cannot represent strings containing double quote characters.
Zero-width tokens
Name
Location
End_of_input
when the end of the input stream is reached
White space
Zero or more whitespace characters, or comments enclosed in /* ... */, are allowed between any two tokens, with the exceptions noted below.
"Longest token matching" is used to resolve conflicts (e.g., in order to match <= as a single token rather than the two tokens < and =).
Whitespace is required between two tokens that have an alphanumeric character or underscore at the edge.
This means: keywords, identifiers, and integer literals.
e.g. ifprint is recognized as an identifier, instead of the keywords if and print.
e.g. 42fred is invalid, and neither recognized as a number nor an identifier.
Whitespace is not allowed inside of tokens (except for chars and strings where they are part of the value).
e.g. & & is invalid, and not interpreted as the && operator.
For example, the following two program fragments are equivalent, and should produce the same token stream except for the line and column positions:
if ( p /* meaning n is prime */ ) {
print ( n , " " ) ;
count = count + 1 ; /* number of primes found so far */
}
if(p){print(n," ");count=count+1;}
Complete list of token names
End_of_input Op_multiply Op_divide Op_mod Op_add Op_subtract
Op_negate Op_not Op_less Op_lessequal Op_greater Op_greaterequal
Op_equal Op_notequal Op_assign Op_and Op_or Keyword_if
Keyword_else Keyword_while Keyword_print Keyword_putc LeftParen RightParen
LeftBrace RightBrace Semicolon Comma Identifier Integer
String
Output Format
The program output should be a sequence of lines, each consisting of the following whitespace-separated fields:
the line number where the token starts
the column number where the token starts
the token name
the token value (only for Identifier, Integer, and String tokens)
the number of spaces between fields is up to you. Neatly aligned is nice, but not a requirement.
This task is intended to be used as part of a pipeline, with the other compiler tasks - for example:
lex < hello.t | parse | gen | vm
Or possibly:
lex hello.t lex.out
parse lex.out parse.out
gen parse.out gen.out
vm gen.out
This implies that the output of this task (the lexical analyzer) should be suitable as input to any of the Syntax Analyzer task programs.
Diagnostics
The following error conditions should be caught:
Error
Example
Empty character constant
''
Unknown escape sequence.
\r
Multi-character constant.
'xx'
End-of-file in comment. Closing comment characters not found.
End-of-file while scanning string literal. Closing string character not found.
End-of-line while scanning string literal. Closing string character not found before end-of-line.
Unrecognized character.
|
Invalid number. Starts like a number, but ends in non-numeric characters.
123abc
Test Cases
Input
Output
Test Case 1:
/*
Hello world
*/
print("Hello, World!\n");
4 1 Keyword_print
4 6 LeftParen
4 7 String "Hello, World!\n"
4 24 RightParen
4 25 Semicolon
5 1 End_of_input
Test Case 2:
/*
Show Ident and Integers
*/
phoenix_number = 142857;
print(phoenix_number, "\n");
4 1 Identifier phoenix_number
4 16 Op_assign
4 18 Integer 142857
4 24 Semicolon
5 1 Keyword_print
5 6 LeftParen
5 7 Identifier phoenix_number
5 21 Comma
5 23 String "\n"
5 27 RightParen
5 28 Semicolon
6 1 End_of_input
Test Case 3:
/*
All lexical tokens - not syntactically correct, but that will
have to wait until syntax analysis
*/
/* Print */ print /* Sub */ -
/* Putc */ putc /* Lss */ <
/* If */ if /* Gtr */ >
/* Else */ else /* Leq */ <=
/* While */ while /* Geq */ >=
/* Lbrace */ { /* Eq */ ==
/* Rbrace */ } /* Neq */ !=
/* Lparen */ ( /* And */ &&
/* Rparen */ ) /* Or */ ||
/* Uminus */ - /* Semi */ ;
/* Not */ ! /* Comma */ ,
/* Mul */ * /* Assign */ =
/* Div */ / /* Integer */ 42
/* Mod */ % /* String */ "String literal"
/* Add */ + /* Ident */ variable_name
/* character literal */ '\n'
/* character literal */ '\\'
/* character literal */ ' '
5 16 Keyword_print
5 40 Op_subtract
6 16 Keyword_putc
6 40 Op_less
7 16 Keyword_if
7 40 Op_greater
8 16 Keyword_else
8 40 Op_lessequal
9 16 Keyword_while
9 40 Op_greaterequal
10 16 LeftBrace
10 40 Op_equal
11 16 RightBrace
11 40 Op_notequal
12 16 LeftParen
12 40 Op_and
13 16 RightParen
13 40 Op_or
14 16 Op_subtract
14 40 Semicolon
15 16 Op_not
15 40 Comma
16 16 Op_multiply
16 40 Op_assign
17 16 Op_divide
17 40 Integer 42
18 16 Op_mod
18 40 String "String literal"
19 16 Op_add
19 40 Identifier variable_name
20 26 Integer 10
21 26 Integer 92
22 26 Integer 32
23 1 End_of_input
Test Case 4:
/*** test printing, embedded \n and comments with lots of '*' ***/
print(42);
print("\nHello World\nGood Bye\nok\n");
print("Print a slash n - \\n.\n");
2 1 Keyword_print
2 6 LeftParen
2 7 Integer 42
2 9 RightParen
2 10 Semicolon
3 1 Keyword_print
3 6 LeftParen
3 7 String "\nHello World\nGood Bye\nok\n"
3 38 RightParen
3 39 Semicolon
4 1 Keyword_print
4 6 LeftParen
4 7 String "Print a slash n - \\n.\n"
4 33 RightParen
4 34 Semicolon
5 1 End_of_input
Additional examples
Your solution should pass all the test cases above and the additional tests found Here.
Reference
The C and Python versions can be considered reference implementations.
Related Tasks
Syntax Analyzer task
Code Generator task
Virtual Machine Interpreter task
AST Interpreter task
| #Racket | Racket |
#lang racket
(require parser-tools/lex)
(define-lex-abbrevs
[letter (union (char-range #\a #\z) (char-range #\A #\Z))]
[digit (char-range #\0 #\9)]
[underscore #\_]
[identifier (concatenation (union letter underscore)
(repetition 0 +inf.0 (union letter digit underscore)))]
[integer (repetition 1 +inf.0 digit)]
[char-content (char-complement (char-set "'\n"))]
[char-literal (union (concatenation #\' char-content #\')
"'\\n'" "'\\\\'")]
[string-content (union (char-complement (char-set "\"\n")))]
[string-literal (union (concatenation #\" (repetition 0 +inf.0 string-content) #\")
"\"\\n\"" "\"\\\\\"")]
[keyword (union "if" "else" "while" "print" "putc")]
[operator (union "*" "/" "%" "+" "-" "-"
"<" "<=" ">" ">=" "==" "!="
"!" "=" "&&" "||")]
[symbol (union "(" ")" "{" "}" ";" ",")]
[comment (concatenation "/*" (complement (concatenation any-string "*/" any-string)) "*/")])
(define operators-ht
(hash "*" 'Op_multiply "/" 'Op_divide "%" 'Op_mod "+" 'Op_add "-" 'Op_subtract
"<" 'Op_less "<=" 'Op_lessequal ">" 'Op_greater ">=" 'Op_greaterequal "==" 'Op_equal
"!=" 'Op_notequal "!" 'Op_not "=" 'Op_assign "&&" 'Op_and "||" 'Op_or))
(define symbols-ht
(hash "(" 'LeftParen ")" 'RightParen
"{" 'LeftBrace "}" 'RightBrace
";" 'Semicolon "," 'Comma))
(define (lexeme->keyword l) (string->symbol (~a "Keyword_" l)))
(define (lexeme->operator l) (hash-ref operators-ht l))
(define (lexeme->symbol l) (hash-ref symbols-ht l))
(define (lexeme->char l) (match l
["'\\\\'" #\\]
["'\\n'" #\newline]
[_ (string-ref l 1)]))
(define (token name [value #f])
(cons name (if value (list value) '())))
(define (lex ip)
(port-count-lines! ip)
(define my-lexer
(lexer-src-pos
[integer (token 'Integer (string->number lexeme))]
[char-literal (token 'Integer (char->integer (lexeme->char lexeme)))]
[string-literal (token 'String lexeme)]
[keyword (token (lexeme->keyword lexeme))]
[operator (token (lexeme->operator lexeme))]
[symbol (token (lexeme->symbol lexeme))]
[comment #f]
[whitespace #f]
[identifier (token 'Identifier lexeme)]
[(eof) (token 'End_of_input)]))
(define (next-token) (my-lexer ip))
next-token)
(define (string->tokens s)
(port->tokens (open-input-string s)))
(define (port->tokens ip)
(define next-token (lex ip))
(let loop ()
(match (next-token)
[(position-token t (position offset line col) _)
(set! col (+ col 1)) ; output is 1-based
(match t
[#f (loop)] ; skip whitespace/comments
[(list 'End_of_input) (list (list line col 'End_of_input))]
[(list name value) (cons (list line col name value) (loop))]
[(list name) (cons (list line col name) (loop))]
[_ (error)])])))
(define test1 #<<TEST
/*
Hello world
*/
print("Hello, World!\n");
TEST
)
(define test2 #<<TEST
/*
Show Ident and Integers
*/
phoenix_number = 142857;
print(phoenix_number, "\n");
TEST
)
(define test3 #<<TEST
/*
All lexical tokens - not syntactically correct, but that will
have to wait until syntax analysis
*/
/* Print */ print /* Sub */ -
/* Putc */ putc /* Lss */ <
/* If */ if /* Gtr */ >
/* Else */ else /* Leq */ <=
/* While */ while /* Geq */ >=
/* Lbrace */ { /* Eq */ ==
/* Rbrace */ } /* Neq */ !=
/* Lparen */ ( /* And */ &&
/* Rparen */ ) /* Or */ ||
/* Uminus */ - /* Semi */ ;
/* Not */ ! /* Comma */ ,
/* Mul */ * /* Assign */ =
/* Div */ / /* Integer */ 42
/* Mod */ % /* String */ "String literal"
/* Add */ + /* Ident */ variable_name
/* character literal */ '\n'
/* character literal */ '\\'
/* character literal */ ' '
TEST
)
(define test4 #<<TEST
/*** test printing, embedded \n and comments with lots of '*' ***/
print(42);
print("\nHello World\nGood Bye\nok\n");
print("Print a slash n - \\n.\n");
TEST
)
(define test5 #<<TEST
count = 1;
while (count < 10) {
print("count is: ", count, "\n");
count = count + 1;
}
TEST
)
(define (display-tokens ts)
(for ([t ts])
(for ([x t])
(display x) (display "\t\t"))
(newline)))
"TEST 1"
(display-tokens (string->tokens test1))
"TEST 2"
(display-tokens (string->tokens test2))
"TEST 3"
(display-tokens (string->tokens test3))
"TEST 4"
(display-tokens (string->tokens test4))
"TEST 5"
(display-tokens (string->tokens test5))
|
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Oberon-2 | Oberon-2 |
MODULE CommandLineArguments;
IMPORT
NPCT:Args,
Out := NPCT:Console;
BEGIN
Out.String("Args number: ");Out.Int(Args.Number(),0);Out.Ln;
Out.String("0.- : ");Out.String(Args.AsString(0));Out.Ln;
Out.String("1.- : ");Out.String(Args.AsString(1));Out.Ln;
Out.String("2.- : ");Out.String(Args.AsString(2));Out.Ln;
Out.String("3.- : ");Out.String(Args.AsString(3));Out.Ln;
Out.String("4.-: ");Out.String(Args.AsString(4));Out.Ln
END CommandLineArguments.
|
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Objeck | Objeck |
class Line {
function : Main(args : String[]) ~ Nil {
each(i : args) {
args[i]->PrintLine();
};
}
}
|
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #Erlang | Erlang | % Erlang comments begin with "%" and extend to the end of the line. |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #ERRE | ERRE |
! Standard ERRE comments begin with ! and extend to the end of the line
PRINT("this is code") ! comment after statement
|
http://rosettacode.org/wiki/Conway%27s_Game_of_Life | Conway's Game of Life | The Game of Life is a cellular automaton devised by the British mathematician John Horton Conway in 1970. It is the best-known example of a cellular automaton.
Conway's game of life is described here:
A cell C is represented by a 1 when alive, or 0 when dead, in an m-by-m (or m×m) square array of cells.
We calculate N - the sum of live cells in C's eight-location neighbourhood, then cell C is alive or dead in the next generation based on the following table:
C N new C
1 0,1 -> 0 # Lonely
1 4,5,6,7,8 -> 0 # Overcrowded
1 2,3 -> 1 # Lives
0 3 -> 1 # It takes three to give birth!
0 0,1,2,4,5,6,7,8 -> 0 # Barren
Assume cells beyond the boundary are always dead.
The "game" is actually a zero-player game, meaning that its evolution is determined by its initial state, needing no input from human players. One interacts with the Game of Life by creating an initial configuration and observing how it evolves.
Task
Although you should test your implementation on more complex examples such as the glider in a larger universe, show the action of the blinker (three adjoining cells in a row all alive), over three generations, in a 3 by 3 grid.
References
Its creator John Conway, explains the game of life. Video from numberphile on youtube.
John Conway Inventing Game of Life - Numberphile video.
Related task
Langton's ant - another well known cellular automaton.
| #Lua | Lua | local function T2D(w,h) local t={} for y=1,h do t[y]={} for x=1,w do t[y][x]=0 end end return t end
local Life = {
new = function(self,w,h)
return setmetatable({ w=w, h=h, gen=1, curr=T2D(w,h), next=T2D(w,h)}, {__index=self})
end,
set = function(self, coords)
for i = 1, #coords, 2 do
self.curr[coords[i+1]][coords[i]] = 1
end
end,
evolve = function(self)
local curr, next = self.curr, self.next
local ym1, y, yp1 = self.h-1, self.h, 1
for i = 1, self.h do
local xm1, x, xp1 = self.w-1, self.w, 1
for j = 1, self.w do
local sum = curr[ym1][xm1] + curr[ym1][x] + curr[ym1][xp1] +
curr[y][xm1] + curr[y][xp1] +
curr[yp1][xm1] + curr[yp1][x] + curr[yp1][xp1]
next[y][x] = ((sum==2) and curr[y][x]) or ((sum==3) and 1) or 0
xm1, x, xp1 = x, xp1, xp1+1
end
ym1, y, yp1 = y, yp1, yp1+1
end
self.curr, self.next, self.gen = self.next, self.curr, self.gen+1
end,
render = function(self)
print("Generation "..self.gen..":")
for y = 1, self.h do
for x = 1, self.w do
io.write(self.curr[y][x]==0 and "□ " or "■ ")
end
print()
end
end
} |
http://rosettacode.org/wiki/Conditional_structures | Conditional structures | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
List the conditional structures offered by a programming language. See Wikipedia: conditionals for descriptions.
Common conditional structures include if-then-else and switch.
Less common are arithmetic if, ternary operator and Hash-based conditionals.
Arithmetic if allows tight control over computed gotos, which optimizers have a hard time to figure out.
| #D.C3.A9j.C3.A0_Vu | Déjà Vu | if a:
pass
elseif b:
pass
else: # c, maybe?
pass |
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #Ruby | Ruby | strings.uniq.one? # all equal?
strings == strings.uniq.sort # ascending? |
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #Rust | Rust | fn strings_are_equal(seq: &[&str]) -> bool {
match seq {
&[] | &[_] => true,
&[x, y, ref tail @ ..] if x == y => strings_are_equal(&[&[y], tail].concat()),
_ => false
}
}
fn asc_strings(seq: &[&str]) -> bool {
match seq {
&[] | &[_] => true,
&[x, y, ref tail @ ..] if x < y => asc_strings(&[&[y], tail].concat()),
_ => false
}
} |
http://rosettacode.org/wiki/Comma_quibbling | Comma quibbling | Comma quibbling is a task originally set by Eric Lippert in his blog.
Task
Write a function to generate a string output which is the concatenation of input words from a list/sequence where:
An input of no words produces the output string of just the two brace characters "{}".
An input of just one word, e.g. ["ABC"], produces the output string of the word inside the two braces, e.g. "{ABC}".
An input of two words, e.g. ["ABC", "DEF"], produces the output string of the two words inside the two braces with the words separated by the string " and ", e.g. "{ABC and DEF}".
An input of three or more words, e.g. ["ABC", "DEF", "G", "H"], produces the output string of all but the last word separated by ", " with the last word separated by " and " and all within braces; e.g. "{ABC, DEF, G and H}".
Test your function with the following series of inputs showing your output here on this page:
[] # (No input words).
["ABC"]
["ABC", "DEF"]
["ABC", "DEF", "G", "H"]
Note: Assume words are non-empty strings of uppercase characters for this task.
| #M2000_Interpreter | M2000 Interpreter |
Module Checkit {
function f$ {
what$=mid$(trim$(letter$),2)
what$=Left$(what$, len(what$)-1)
flush ' erase any argument from stack
Data param$(what$)
m=stack.size
document resp$="{"
if m>2 then {
shift m-1, 2 ' get last two as first two
push letter$+" and "+letter$
m-- ' one less
shiftback m ' move to last position
}
while not empty {
resp$=letter$+if$(not empty->", ", "")
}
=resp$+"}"
}
\\ we use ? for Print
? f$({[]})
? f$({["ABC"]})
? f$({["ABC", "DEF"]})
? f$({["ABC","DEF", "G", "H"]})
}
Checkit
|
http://rosettacode.org/wiki/Comma_quibbling | Comma quibbling | Comma quibbling is a task originally set by Eric Lippert in his blog.
Task
Write a function to generate a string output which is the concatenation of input words from a list/sequence where:
An input of no words produces the output string of just the two brace characters "{}".
An input of just one word, e.g. ["ABC"], produces the output string of the word inside the two braces, e.g. "{ABC}".
An input of two words, e.g. ["ABC", "DEF"], produces the output string of the two words inside the two braces with the words separated by the string " and ", e.g. "{ABC and DEF}".
An input of three or more words, e.g. ["ABC", "DEF", "G", "H"], produces the output string of all but the last word separated by ", " with the last word separated by " and " and all within braces; e.g. "{ABC, DEF, G and H}".
Test your function with the following series of inputs showing your output here on this page:
[] # (No input words).
["ABC"]
["ABC", "DEF"]
["ABC", "DEF", "G", "H"]
Note: Assume words are non-empty strings of uppercase characters for this task.
| #Maple | Maple | Quibble := proc( los )
uses StringTools;
Fence( proc()
if los = [] then
""
elif numelems( los ) = 1 then
los[ 1 ]
else
cat( Join( los[ 1 .. -2 ], ", " ), " and ", los[ -1 ] )
end if
end(), "{", "}" )
end proc: |
http://rosettacode.org/wiki/Combinations_with_repetitions | Combinations with repetitions | The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of those sets is chosen from
S
{\displaystyle S}
.
In the real world, it is about choosing sets where there is a “large” supply of each type of element and where the order of choice does not matter.
For example:
Q: How many ways can a person choose two doughnuts from a store selling three types of doughnut: iced, jam, and plain? (i.e.,
S
{\displaystyle S}
is
{
i
c
e
d
,
j
a
m
,
p
l
a
i
n
}
{\displaystyle \{\mathrm {iced} ,\mathrm {jam} ,\mathrm {plain} \}}
,
|
S
|
=
3
{\displaystyle |S|=3}
, and
k
=
2
{\displaystyle k=2}
.)
A: 6: {iced, iced}; {iced, jam}; {iced, plain}; {jam, jam}; {jam, plain}; {plain, plain}.
Note that both the order of items within a pair, and the order of the pairs given in the answer is not significant; the pairs represent multisets.
Also note that doughnut can also be spelled donut.
Task
Write a function/program/routine/.. to generate all the combinations with repetitions of
n
{\displaystyle n}
types of things taken
k
{\displaystyle k}
at a time and use it to show an answer to the doughnut example above.
For extra credit, use the function to compute and show just the number of ways of choosing three doughnuts from a choice of ten types of doughnut. Do not show the individual choices for this part.
References
k-combination with repetitions
See also
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #Ring | Ring |
# Project : Combinations with repetitions
n = 2
k = 3
temp = []
comb = []
num = com(n, k)
combinations(n, k)
comb = sortfirst(comb, 1)
see showarray(comb) + nl
func combinations(n, k)
while true
temp = []
for nr = 1 to k
tm = random(n-1) + 1
add(temp, tm)
next
add(comb, temp)
for p = 1 to len(comb) - 1
for q = p + 1 to len(comb)
if (comb[p][1] = comb[q][1]) and (comb[p][2] = comb[q][2]) and (comb[p][3] = comb[q][3])
del(comb, p)
ok
next
next
if len(comb) = num
exit
ok
end
func com(n, k)
res = pow(n, k)
return res
func showarray(vect)
svect = ""
for nrs = 1 to len(vect)
svect = "[" + vect[nrs][1] + " " + vect[nrs][2] + " " + vect[nrs][3] + "]" + nl
see svect
next
Func sortfirst(alist, ind)
aList = sort(aList,ind)
for n = 1 to len(alist)-1
for m= n + 1 to len(aList)
if alist[n][1] = alist[m][1] and alist[m][2] < alist[n][2]
temp = alist[n]
alist[n] = alist[m]
alist[m] = temp
ok
next
next
for n = 1 to len(alist)-1
for m= n + 1 to len(aList)
if alist[n][1] = alist[m][1] and alist[n][2] = alist[m][2] and alist[m][3] < alist[n][3]
temp = alist[n]
alist[n] = alist[m]
alist[m] = temp
ok
next
next
return aList
|
http://rosettacode.org/wiki/Combinations_with_repetitions | Combinations with repetitions | The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of those sets is chosen from
S
{\displaystyle S}
.
In the real world, it is about choosing sets where there is a “large” supply of each type of element and where the order of choice does not matter.
For example:
Q: How many ways can a person choose two doughnuts from a store selling three types of doughnut: iced, jam, and plain? (i.e.,
S
{\displaystyle S}
is
{
i
c
e
d
,
j
a
m
,
p
l
a
i
n
}
{\displaystyle \{\mathrm {iced} ,\mathrm {jam} ,\mathrm {plain} \}}
,
|
S
|
=
3
{\displaystyle |S|=3}
, and
k
=
2
{\displaystyle k=2}
.)
A: 6: {iced, iced}; {iced, jam}; {iced, plain}; {jam, jam}; {jam, plain}; {plain, plain}.
Note that both the order of items within a pair, and the order of the pairs given in the answer is not significant; the pairs represent multisets.
Also note that doughnut can also be spelled donut.
Task
Write a function/program/routine/.. to generate all the combinations with repetitions of
n
{\displaystyle n}
types of things taken
k
{\displaystyle k}
at a time and use it to show an answer to the doughnut example above.
For extra credit, use the function to compute and show just the number of ways of choosing three doughnuts from a choice of ten types of doughnut. Do not show the individual choices for this part.
References
k-combination with repetitions
See also
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #Ruby | Ruby | possible_doughnuts = ['iced', 'jam', 'plain'].repeated_combination(2)
puts "There are #{possible_doughnuts.count} possible doughnuts:"
possible_doughnuts.each{|doughnut_combi| puts doughnut_combi.join(' and ')}
# Extra credit
possible_doughnuts = [*1..1000].repeated_combination(30)
# size returns the size of the enumerator, or nil if it can’t be calculated lazily.
puts "", "#{possible_doughnuts.size} ways to order 30 donuts given 1000 types."
|
http://rosettacode.org/wiki/Compiler/lexical_analyzer | Compiler/lexical analyzer | Definition from Wikipedia:
Lexical analysis is the process of converting a sequence of characters (such as in a computer program or web page) into a sequence of tokens (strings with an identified "meaning"). A program that performs lexical analysis may be called a lexer, tokenizer, or scanner (though "scanner" is also used to refer to the first stage of a lexer).
Task[edit]
Create a lexical analyzer for the simple programming language specified below. The
program should read input from a file and/or stdin, and write output to a file and/or
stdout. If the language being used has a lexer module/library/class, it would be great
if two versions of the solution are provided: One without the lexer module, and one with.
Input Specification
The simple programming language to be analyzed is more or less a subset of C. It supports the following tokens:
Operators
Name
Common name
Character sequence
Op_multiply
multiply
*
Op_divide
divide
/
Op_mod
mod
%
Op_add
plus
+
Op_subtract
minus
-
Op_negate
unary minus
-
Op_less
less than
<
Op_lessequal
less than or equal
<=
Op_greater
greater than
>
Op_greaterequal
greater than or equal
>=
Op_equal
equal
==
Op_notequal
not equal
!=
Op_not
unary not
!
Op_assign
assignment
=
Op_and
logical and
&&
Op_or
logical or
¦¦
The - token should always be interpreted as Op_subtract by the lexer. Turning some Op_subtract into Op_negate will be the job of the syntax analyzer, which is not part of this task.
Symbols
Name
Common name
Character
LeftParen
left parenthesis
(
RightParen
right parenthesis
)
LeftBrace
left brace
{
RightBrace
right brace
}
Semicolon
semi-colon
;
Comma
comma
,
Keywords
Name
Character sequence
Keyword_if
if
Keyword_else
else
Keyword_while
while
Keyword_print
print
Keyword_putc
putc
Identifiers and literals
These differ from the the previous tokens, in that each occurrence of them has a value associated with it.
Name
Common name
Format description
Format regex
Value
Identifier
identifier
one or more letter/number/underscore characters, but not starting with a number
[_a-zA-Z][_a-zA-Z0-9]*
as is
Integer
integer literal
one or more digits
[0-9]+
as is, interpreted as a number
Integer
char literal
exactly one character (anything except newline or single quote) or one of the allowed escape sequences, enclosed by single quotes
'([^'\n]|\\n|\\\\)'
the ASCII code point number of the character, e.g. 65 for 'A' and 10 for '\n'
String
string literal
zero or more characters (anything except newline or double quote), enclosed by double quotes
"[^"\n]*"
the characters without the double quotes and with escape sequences converted
For char and string literals, the \n escape sequence is supported to represent a new-line character.
For char and string literals, to represent a backslash, use \\.
No other special sequences are supported. This means that:
Char literals cannot represent a single quote character (value 39).
String literals cannot represent strings containing double quote characters.
Zero-width tokens
Name
Location
End_of_input
when the end of the input stream is reached
White space
Zero or more whitespace characters, or comments enclosed in /* ... */, are allowed between any two tokens, with the exceptions noted below.
"Longest token matching" is used to resolve conflicts (e.g., in order to match <= as a single token rather than the two tokens < and =).
Whitespace is required between two tokens that have an alphanumeric character or underscore at the edge.
This means: keywords, identifiers, and integer literals.
e.g. ifprint is recognized as an identifier, instead of the keywords if and print.
e.g. 42fred is invalid, and neither recognized as a number nor an identifier.
Whitespace is not allowed inside of tokens (except for chars and strings where they are part of the value).
e.g. & & is invalid, and not interpreted as the && operator.
For example, the following two program fragments are equivalent, and should produce the same token stream except for the line and column positions:
if ( p /* meaning n is prime */ ) {
print ( n , " " ) ;
count = count + 1 ; /* number of primes found so far */
}
if(p){print(n," ");count=count+1;}
Complete list of token names
End_of_input Op_multiply Op_divide Op_mod Op_add Op_subtract
Op_negate Op_not Op_less Op_lessequal Op_greater Op_greaterequal
Op_equal Op_notequal Op_assign Op_and Op_or Keyword_if
Keyword_else Keyword_while Keyword_print Keyword_putc LeftParen RightParen
LeftBrace RightBrace Semicolon Comma Identifier Integer
String
Output Format
The program output should be a sequence of lines, each consisting of the following whitespace-separated fields:
the line number where the token starts
the column number where the token starts
the token name
the token value (only for Identifier, Integer, and String tokens)
the number of spaces between fields is up to you. Neatly aligned is nice, but not a requirement.
This task is intended to be used as part of a pipeline, with the other compiler tasks - for example:
lex < hello.t | parse | gen | vm
Or possibly:
lex hello.t lex.out
parse lex.out parse.out
gen parse.out gen.out
vm gen.out
This implies that the output of this task (the lexical analyzer) should be suitable as input to any of the Syntax Analyzer task programs.
Diagnostics
The following error conditions should be caught:
Error
Example
Empty character constant
''
Unknown escape sequence.
\r
Multi-character constant.
'xx'
End-of-file in comment. Closing comment characters not found.
End-of-file while scanning string literal. Closing string character not found.
End-of-line while scanning string literal. Closing string character not found before end-of-line.
Unrecognized character.
|
Invalid number. Starts like a number, but ends in non-numeric characters.
123abc
Test Cases
Input
Output
Test Case 1:
/*
Hello world
*/
print("Hello, World!\n");
4 1 Keyword_print
4 6 LeftParen
4 7 String "Hello, World!\n"
4 24 RightParen
4 25 Semicolon
5 1 End_of_input
Test Case 2:
/*
Show Ident and Integers
*/
phoenix_number = 142857;
print(phoenix_number, "\n");
4 1 Identifier phoenix_number
4 16 Op_assign
4 18 Integer 142857
4 24 Semicolon
5 1 Keyword_print
5 6 LeftParen
5 7 Identifier phoenix_number
5 21 Comma
5 23 String "\n"
5 27 RightParen
5 28 Semicolon
6 1 End_of_input
Test Case 3:
/*
All lexical tokens - not syntactically correct, but that will
have to wait until syntax analysis
*/
/* Print */ print /* Sub */ -
/* Putc */ putc /* Lss */ <
/* If */ if /* Gtr */ >
/* Else */ else /* Leq */ <=
/* While */ while /* Geq */ >=
/* Lbrace */ { /* Eq */ ==
/* Rbrace */ } /* Neq */ !=
/* Lparen */ ( /* And */ &&
/* Rparen */ ) /* Or */ ||
/* Uminus */ - /* Semi */ ;
/* Not */ ! /* Comma */ ,
/* Mul */ * /* Assign */ =
/* Div */ / /* Integer */ 42
/* Mod */ % /* String */ "String literal"
/* Add */ + /* Ident */ variable_name
/* character literal */ '\n'
/* character literal */ '\\'
/* character literal */ ' '
5 16 Keyword_print
5 40 Op_subtract
6 16 Keyword_putc
6 40 Op_less
7 16 Keyword_if
7 40 Op_greater
8 16 Keyword_else
8 40 Op_lessequal
9 16 Keyword_while
9 40 Op_greaterequal
10 16 LeftBrace
10 40 Op_equal
11 16 RightBrace
11 40 Op_notequal
12 16 LeftParen
12 40 Op_and
13 16 RightParen
13 40 Op_or
14 16 Op_subtract
14 40 Semicolon
15 16 Op_not
15 40 Comma
16 16 Op_multiply
16 40 Op_assign
17 16 Op_divide
17 40 Integer 42
18 16 Op_mod
18 40 String "String literal"
19 16 Op_add
19 40 Identifier variable_name
20 26 Integer 10
21 26 Integer 92
22 26 Integer 32
23 1 End_of_input
Test Case 4:
/*** test printing, embedded \n and comments with lots of '*' ***/
print(42);
print("\nHello World\nGood Bye\nok\n");
print("Print a slash n - \\n.\n");
2 1 Keyword_print
2 6 LeftParen
2 7 Integer 42
2 9 RightParen
2 10 Semicolon
3 1 Keyword_print
3 6 LeftParen
3 7 String "\nHello World\nGood Bye\nok\n"
3 38 RightParen
3 39 Semicolon
4 1 Keyword_print
4 6 LeftParen
4 7 String "Print a slash n - \\n.\n"
4 33 RightParen
4 34 Semicolon
5 1 End_of_input
Additional examples
Your solution should pass all the test cases above and the additional tests found Here.
Reference
The C and Python versions can be considered reference implementations.
Related Tasks
Syntax Analyzer task
Code Generator task
Virtual Machine Interpreter task
AST Interpreter task
| #Raku | Raku | grammar tiny_C {
rule TOP { ^ <.whitespace>? <tokens> + % <.whitespace> <.whitespace> <eoi> }
rule whitespace { [ <comment> + % <ws> | <ws> ] }
token comment { '/*' ~ '*/' .*? }
token tokens {
[
| <operator> { make $/<operator>.ast }
| <keyword> { make $/<keyword>.ast }
| <symbol> { make $/<symbol>.ast }
| <identifier> { make $/<identifier>.ast }
| <integer> { make $/<integer>.ast }
| <char> { make $/<char>.ast }
| <string> { make $/<string>.ast }
| <error>
]
}
proto token operator {*}
token operator:sym<*> { '*' { make 'Op_multiply' } }
token operator:sym</> { '/'<!before '*'> { make 'Op_divide' } }
token operator:sym<%> { '%' { make 'Op_mod' } }
token operator:sym<+> { '+' { make 'Op_add' } }
token operator:sym<-> { '-' { make 'Op_subtract' } }
token operator:sym('<='){ '<=' { make 'Op_lessequal' } }
token operator:sym('<') { '<' { make 'Op_less' } }
token operator:sym('>='){ '>=' { make 'Op_greaterequal'} }
token operator:sym('>') { '>' { make 'Op_greater' } }
token operator:sym<==> { '==' { make 'Op_equal' } }
token operator:sym<!=> { '!=' { make 'Op_notequal' } }
token operator:sym<!> { '!' { make 'Op_not' } }
token operator:sym<=> { '=' { make 'Op_assign' } }
token operator:sym<&&> { '&&' { make 'Op_and' } }
token operator:sym<||> { '||' { make 'Op_or' } }
proto token keyword {*}
token keyword:sym<if> { 'if' { make 'Keyword_if' } }
token keyword:sym<else> { 'else' { make 'Keyword_else' } }
token keyword:sym<putc> { 'putc' { make 'Keyword_putc' } }
token keyword:sym<while> { 'while' { make 'Keyword_while' } }
token keyword:sym<print> { 'print' { make 'Keyword_print' } }
proto token symbol {*}
token symbol:sym<(> { '(' { make 'LeftParen' } }
token symbol:sym<)> { ')' { make 'RightParen' } }
token symbol:sym<{> { '{' { make 'LeftBrace' } }
token symbol:sym<}> { '}' { make 'RightBrace' } }
token symbol:sym<;> { ';' { make 'Semicolon' } }
token symbol:sym<,> { ',' { make 'Comma' } }
token identifier { <[_A..Za..z]><[_A..Za..z0..9]>* { make 'Identifier ' ~ $/ } }
token integer { <[0..9]>+ { make 'Integer ' ~ $/ } }
token char {
'\'' [<-[']> | '\n' | '\\\\'] '\''
{ make 'Char_Literal ' ~ $/.subst("\\n", "\n").substr(1, *-1).ord }
}
token string {
'"' <-["\n]>* '"' #'
{
make 'String ' ~ $/;
note 'Error: Unknown escape sequence.' and exit if (~$/ ~~ m:r/ <!after <[\\]>>[\\<-[n\\]>]<!before <[\\]>> /);
}
}
token eoi { $ { make 'End_of_input' } }
token error {
| '\'''\'' { note 'Error: Empty character constant.' and exit }
| '\'' <-[']> ** {2..*} '\'' { note 'Error: Multi-character constant.' and exit }
| '/*' <-[*]>* $ { note 'Error: End-of-file in comment.' and exit }
| '"' <-["]>* $ { note 'Error: End-of-file in string.' and exit }
| '"' <-["]>*? \n { note 'Error: End of line in string.' and exit } #'
}
}
sub parse_it ( $c_code ) {
my $l;
my @pos = gather for $c_code.lines>>.chars.kv -> $line, $v {
take [ $line + 1, $_ ] for 1 .. ($v+1); # v+1 for newline
$l = $line+2;
}
@pos.push: [ $l, 1 ]; # capture eoi
for flat $c_code<tokens>.list, $c_code<eoi> -> $m {
say join "\t", @pos[$m.from].fmt('%3d'), $m.ast;
}
}
my $tokenizer = tiny_C.parse(@*ARGS[0].IO.slurp);
parse_it( $tokenizer ); |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Objective-C | Objective-C | NSArray *args = [[NSProcessInfo processInfo] arguments];
NSLog(@"This program is named %@.", [args objectAtIndex:0]);
NSLog(@"There are %d arguments.", [args count] - 1);
for (i = 1; i < [args count]; ++i){
NSLog(@"the argument #%d is %@", i, [args objectAtIndex:i]);
} |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #OCaml | OCaml | let () =
Printf.printf "This program is named %s.\n" Sys.argv.(0);
for i = 1 to Array.length Sys.argv - 1 do
Printf.printf "the argument #%d is %s\n" i Sys.argv.(i)
done |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #Euphoria | Euphoria | -- This is a comment |
http://rosettacode.org/wiki/Conway%27s_Game_of_Life | Conway's Game of Life | The Game of Life is a cellular automaton devised by the British mathematician John Horton Conway in 1970. It is the best-known example of a cellular automaton.
Conway's game of life is described here:
A cell C is represented by a 1 when alive, or 0 when dead, in an m-by-m (or m×m) square array of cells.
We calculate N - the sum of live cells in C's eight-location neighbourhood, then cell C is alive or dead in the next generation based on the following table:
C N new C
1 0,1 -> 0 # Lonely
1 4,5,6,7,8 -> 0 # Overcrowded
1 2,3 -> 1 # Lives
0 3 -> 1 # It takes three to give birth!
0 0,1,2,4,5,6,7,8 -> 0 # Barren
Assume cells beyond the boundary are always dead.
The "game" is actually a zero-player game, meaning that its evolution is determined by its initial state, needing no input from human players. One interacts with the Game of Life by creating an initial configuration and observing how it evolves.
Task
Although you should test your implementation on more complex examples such as the glider in a larger universe, show the action of the blinker (three adjoining cells in a row all alive), over three generations, in a 3 by 3 grid.
References
Its creator John Conway, explains the game of life. Video from numberphile on youtube.
John Conway Inventing Game of Life - Numberphile video.
Related task
Langton's ant - another well known cellular automaton.
| #ksh | ksh |
#!/bin/ksh
# # Version AJM 93u+ 2012-08-01
# Conway's Game of Life
# # Variables:
#
integer RAND_MAX=32767
LIFE="�[07m �[m"
NULL=" "
typeset -a char=( "$NULL" "$LIFE" )
# # Input x y or default to 30x30, positive integers only
#
integer h=${1:-30} ; h=$(( h<=0 ? 30 : h )) # Height (y)
integer w=${2:-30} ; w=$(( w<=0 ? 30 : w )) # Width (x)
# # Functions:
#
# # Function _display(map, h, w)
#
function _display {
typeset _dmap ; nameref _dmap="$1"
typeset _h _w ; integer _h=$2 _w=$3
typeset _x _y ; integer _x _y
printf %s "�[H"
for (( _y=0; _y<_h; _y++ )); do
for (( _x=0; _x<_w; _x++ )); do
printf %s "${char[_dmap[_y][_x]]}"
done
printf "%s\n"
done
}
# # Function _evolve(h, w)
#
_evolve() {
typeset _h _w ; integer _h=$1 _w=$2
typeset _x _y _n _y1 _x1 ; integer _x _y _n _y1 _x1
typeset _new _newdef ; typeset -a _new
for (( _y=0; _y<_h; _y++ )); do
for (( _x=0; _x<_w; _x++ )); do
_n=0
for (( _y1=_y-1; _y1<=_y+1; _y1++ )); do
for (( _x1=_x-1; _x1<=_x+1; _x1++ )); do
(( _map[$(( (_y1 + _h) % _h ))][$(( (_x1 + _w) % _w ))] )) && (( _n++ ))
done
done
(( _map[_y][_x] )) && (( _n-- ))
_new[_y][_x]=$(( (_n==3) || (_n==2 && _map[_y][_x]) ))
done
done
for (( _y=0; _y<_h; _y++ )); do
for (( _x=0; _x<_w; _x++ )); do
_map[_y][_x]=${_new[_y][_x]}
done
done
}
# # Function _game(h, w)
#
function _game {
typeset _h ; integer _h=$1
typeset _w ; integer _w=$2
typeset _x _y ; integer _x _y
typeset -a _map
for (( _y=0 ; _y<_h ; _y++ )); do
for (( _x=0 ; _x<_h ; _x++ )); do
_map[_x][_y]=$(( RANDOM < RAND_MAX / 10 ? 1 : 0 )) # seed map
done
done
while : ; do
_display _map ${_h} ${_w}
_evolve ${_h} ${_w}
sleep 0.2
done
}
######
# main #
######
_game ${h} ${w}
|
http://rosettacode.org/wiki/Conditional_structures | Conditional structures | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
List the conditional structures offered by a programming language. See Wikipedia: conditionals for descriptions.
Common conditional structures include if-then-else and switch.
Less common are arithmetic if, ternary operator and Hash-based conditionals.
Arithmetic if allows tight control over computed gotos, which optimizers have a hard time to figure out.
| #E | E | if (okay) {
println("okay")
} else if (!okay) {
println("not okay")
} else {
println("not my day")
} |
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #S-lang | S-lang | define equal_sl(sarr)
{
variable n = length(sarr), a0, i;
if (n < 2) return 1;
a0 = sarr[0];
_for i (1, length(sarr)-1, 1)
if (sarr[i] != a0) return 0;
return 1;
}
define ascending_sl(sarr) {
variable n = length(sarr), a0, i;
if (n < 2) return 1;
_for i (0, length(sarr)-2, 1)
if (sarr[i] >= sarr[i+1]) return 0;
return 1;
}
define equal_ai(sarr) {
if (length(sarr) < 2) return 1;
variable s0 = sarr[0];
return all(sarr[[1:]] == s0);
}
define ascending_ai(sarr) {
variable la = length(sarr);
if (la < 2) return 1;
return all(sarr[[0:la-2]] < sarr[[1:la-1]]);
}
define atest(a) {
() = printf("\n");
print(a);
() = printf("equal_sl=%d, ascending_sl=%d\n",
equal_sl(a), ascending_sl(a));
() = printf("equal_ai=%d, ascending_ai=%d\n",
equal_ai(a), ascending_ai(a));
}
atest(["AA","BB","CC"]);
atest(["AA","AA","AA"]);
atest(["AA","CC","BB"]);
atest(["AA","ACB","BB","CC"]);
atest(["single_element"]);
atest(NULL);
|
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #Scala | Scala |
def strings_are_equal(seq:List[String]):Boolean = seq match {
case Nil => true
case s::Nil => true
case el1 :: el2 :: tail => el1==el2 && strings_are_equal(el2::tail)
}
def asc_strings(seq:List[String]):Boolean = seq match {
case Nil => true
case s::Nil => true
case el1 :: el2 :: tail => el1.compareTo(el2) < 0
}
|
http://rosettacode.org/wiki/Comma_quibbling | Comma quibbling | Comma quibbling is a task originally set by Eric Lippert in his blog.
Task
Write a function to generate a string output which is the concatenation of input words from a list/sequence where:
An input of no words produces the output string of just the two brace characters "{}".
An input of just one word, e.g. ["ABC"], produces the output string of the word inside the two braces, e.g. "{ABC}".
An input of two words, e.g. ["ABC", "DEF"], produces the output string of the two words inside the two braces with the words separated by the string " and ", e.g. "{ABC and DEF}".
An input of three or more words, e.g. ["ABC", "DEF", "G", "H"], produces the output string of all but the last word separated by ", " with the last word separated by " and " and all within braces; e.g. "{ABC, DEF, G and H}".
Test your function with the following series of inputs showing your output here on this page:
[] # (No input words).
["ABC"]
["ABC", "DEF"]
["ABC", "DEF", "G", "H"]
Note: Assume words are non-empty strings of uppercase characters for this task.
| #Mathematica_.2F_Wolfram_Language | Mathematica / Wolfram Language | quibble[words___] :=
ToString@{StringJoin@@
Replace[Riffle[{words}, ", "],
{most__, ", ", last_} -> {most, " and ", last}]} |
http://rosettacode.org/wiki/Comma_quibbling | Comma quibbling | Comma quibbling is a task originally set by Eric Lippert in his blog.
Task
Write a function to generate a string output which is the concatenation of input words from a list/sequence where:
An input of no words produces the output string of just the two brace characters "{}".
An input of just one word, e.g. ["ABC"], produces the output string of the word inside the two braces, e.g. "{ABC}".
An input of two words, e.g. ["ABC", "DEF"], produces the output string of the two words inside the two braces with the words separated by the string " and ", e.g. "{ABC and DEF}".
An input of three or more words, e.g. ["ABC", "DEF", "G", "H"], produces the output string of all but the last word separated by ", " with the last word separated by " and " and all within braces; e.g. "{ABC, DEF, G and H}".
Test your function with the following series of inputs showing your output here on this page:
[] # (No input words).
["ABC"]
["ABC", "DEF"]
["ABC", "DEF", "G", "H"]
Note: Assume words are non-empty strings of uppercase characters for this task.
| #MATLAB_.2F_Octave | MATLAB / Octave |
function r = comma_quibbling(varargin)
if isempty(varargin)
r = '';
elseif length(varargin)==1;
r = varargin{1};
else
r = [varargin{end-1},' and ', varargin{end}];
for k=length(varargin)-2:-1:1,
r = [varargin{k}, ', ', r];
end
end
end;
|
http://rosettacode.org/wiki/Combinations_with_repetitions | Combinations with repetitions | The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of those sets is chosen from
S
{\displaystyle S}
.
In the real world, it is about choosing sets where there is a “large” supply of each type of element and where the order of choice does not matter.
For example:
Q: How many ways can a person choose two doughnuts from a store selling three types of doughnut: iced, jam, and plain? (i.e.,
S
{\displaystyle S}
is
{
i
c
e
d
,
j
a
m
,
p
l
a
i
n
}
{\displaystyle \{\mathrm {iced} ,\mathrm {jam} ,\mathrm {plain} \}}
,
|
S
|
=
3
{\displaystyle |S|=3}
, and
k
=
2
{\displaystyle k=2}
.)
A: 6: {iced, iced}; {iced, jam}; {iced, plain}; {jam, jam}; {jam, plain}; {plain, plain}.
Note that both the order of items within a pair, and the order of the pairs given in the answer is not significant; the pairs represent multisets.
Also note that doughnut can also be spelled donut.
Task
Write a function/program/routine/.. to generate all the combinations with repetitions of
n
{\displaystyle n}
types of things taken
k
{\displaystyle k}
at a time and use it to show an answer to the doughnut example above.
For extra credit, use the function to compute and show just the number of ways of choosing three doughnuts from a choice of ten types of doughnut. Do not show the individual choices for this part.
References
k-combination with repetitions
See also
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #Rust | Rust |
// Iterator for the combinations of `arr` with `k` elements with repetitions.
// Yields the combinations in lexicographical order.
struct CombinationsWithRepetitions<'a, T: 'a> {
// source array to get combinations from
arr: &'a [T],
// length of the combinations
k: u32,
// current counts of each object that represent the next combination
counts: Vec<u32>,
// whether there are any combinations left
remaining: bool,
}
impl<'a, T> CombinationsWithRepetitions<'a, T> {
fn new(arr: &[T], k: u32) -> CombinationsWithRepetitions<T> {
let mut counts = vec![0; arr.len()];
counts[arr.len() - 1] = k;
CombinationsWithRepetitions {
arr,
k,
counts,
remaining: true,
}
}
}
impl<'a, T> Iterator for CombinationsWithRepetitions<'a, T> {
type Item = Vec<&'a T>;
fn next(&mut self) -> Option<Vec<&'a T>> {
if !self.remaining {
return None;
}
let mut comb = Vec::new();
for (count, item) in self.counts.iter().zip(self.arr.iter()) {
for _ in 0..*count {
comb.push(item);
}
}
// this is lexicographically largest, and thus the last combination
if self.counts[0] == self.k {
self.remaining = false;
} else {
let n = self.counts.len();
for i in (1..n).rev() {
if self.counts[i] > 0 {
let original_value = self.counts[i];
self.counts[i - 1] += 1;
for j in i..(n - 1) {
self.counts[j] = 0;
}
self.counts[n - 1] = original_value - 1;
break;
}
}
}
Some(comb)
}
}
fn main() {
let collection = vec!["iced", "jam", "plain"];
for comb in CombinationsWithRepetitions::new(&collection, 2) {
for item in &comb {
print!("{} ", item)
}
println!()
}
}
|
http://rosettacode.org/wiki/Combinations_with_repetitions | Combinations with repetitions | The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of those sets is chosen from
S
{\displaystyle S}
.
In the real world, it is about choosing sets where there is a “large” supply of each type of element and where the order of choice does not matter.
For example:
Q: How many ways can a person choose two doughnuts from a store selling three types of doughnut: iced, jam, and plain? (i.e.,
S
{\displaystyle S}
is
{
i
c
e
d
,
j
a
m
,
p
l
a
i
n
}
{\displaystyle \{\mathrm {iced} ,\mathrm {jam} ,\mathrm {plain} \}}
,
|
S
|
=
3
{\displaystyle |S|=3}
, and
k
=
2
{\displaystyle k=2}
.)
A: 6: {iced, iced}; {iced, jam}; {iced, plain}; {jam, jam}; {jam, plain}; {plain, plain}.
Note that both the order of items within a pair, and the order of the pairs given in the answer is not significant; the pairs represent multisets.
Also note that doughnut can also be spelled donut.
Task
Write a function/program/routine/.. to generate all the combinations with repetitions of
n
{\displaystyle n}
types of things taken
k
{\displaystyle k}
at a time and use it to show an answer to the doughnut example above.
For extra credit, use the function to compute and show just the number of ways of choosing three doughnuts from a choice of ten types of doughnut. Do not show the individual choices for this part.
References
k-combination with repetitions
See also
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #Scala | Scala |
object CombinationsWithRepetition {
def multi[A](as: List[A], k: Int): List[List[A]] =
(List.fill(k)(as)).flatten.combinations(k).toList
def main(args: Array[String]): Unit = {
val doughnuts = multi(List("iced", "jam", "plain"), 2)
for (combo <- doughnuts) println(combo.mkString(","))
val bonus = multi(List(0,1,2,3,4,5,6,7,8,9), 3).size
println("There are "+bonus+" ways to choose 3 items from 10 choices")
}
}
|
http://rosettacode.org/wiki/Compiler/lexical_analyzer | Compiler/lexical analyzer | Definition from Wikipedia:
Lexical analysis is the process of converting a sequence of characters (such as in a computer program or web page) into a sequence of tokens (strings with an identified "meaning"). A program that performs lexical analysis may be called a lexer, tokenizer, or scanner (though "scanner" is also used to refer to the first stage of a lexer).
Task[edit]
Create a lexical analyzer for the simple programming language specified below. The
program should read input from a file and/or stdin, and write output to a file and/or
stdout. If the language being used has a lexer module/library/class, it would be great
if two versions of the solution are provided: One without the lexer module, and one with.
Input Specification
The simple programming language to be analyzed is more or less a subset of C. It supports the following tokens:
Operators
Name
Common name
Character sequence
Op_multiply
multiply
*
Op_divide
divide
/
Op_mod
mod
%
Op_add
plus
+
Op_subtract
minus
-
Op_negate
unary minus
-
Op_less
less than
<
Op_lessequal
less than or equal
<=
Op_greater
greater than
>
Op_greaterequal
greater than or equal
>=
Op_equal
equal
==
Op_notequal
not equal
!=
Op_not
unary not
!
Op_assign
assignment
=
Op_and
logical and
&&
Op_or
logical or
¦¦
The - token should always be interpreted as Op_subtract by the lexer. Turning some Op_subtract into Op_negate will be the job of the syntax analyzer, which is not part of this task.
Symbols
Name
Common name
Character
LeftParen
left parenthesis
(
RightParen
right parenthesis
)
LeftBrace
left brace
{
RightBrace
right brace
}
Semicolon
semi-colon
;
Comma
comma
,
Keywords
Name
Character sequence
Keyword_if
if
Keyword_else
else
Keyword_while
while
Keyword_print
print
Keyword_putc
putc
Identifiers and literals
These differ from the the previous tokens, in that each occurrence of them has a value associated with it.
Name
Common name
Format description
Format regex
Value
Identifier
identifier
one or more letter/number/underscore characters, but not starting with a number
[_a-zA-Z][_a-zA-Z0-9]*
as is
Integer
integer literal
one or more digits
[0-9]+
as is, interpreted as a number
Integer
char literal
exactly one character (anything except newline or single quote) or one of the allowed escape sequences, enclosed by single quotes
'([^'\n]|\\n|\\\\)'
the ASCII code point number of the character, e.g. 65 for 'A' and 10 for '\n'
String
string literal
zero or more characters (anything except newline or double quote), enclosed by double quotes
"[^"\n]*"
the characters without the double quotes and with escape sequences converted
For char and string literals, the \n escape sequence is supported to represent a new-line character.
For char and string literals, to represent a backslash, use \\.
No other special sequences are supported. This means that:
Char literals cannot represent a single quote character (value 39).
String literals cannot represent strings containing double quote characters.
Zero-width tokens
Name
Location
End_of_input
when the end of the input stream is reached
White space
Zero or more whitespace characters, or comments enclosed in /* ... */, are allowed between any two tokens, with the exceptions noted below.
"Longest token matching" is used to resolve conflicts (e.g., in order to match <= as a single token rather than the two tokens < and =).
Whitespace is required between two tokens that have an alphanumeric character or underscore at the edge.
This means: keywords, identifiers, and integer literals.
e.g. ifprint is recognized as an identifier, instead of the keywords if and print.
e.g. 42fred is invalid, and neither recognized as a number nor an identifier.
Whitespace is not allowed inside of tokens (except for chars and strings where they are part of the value).
e.g. & & is invalid, and not interpreted as the && operator.
For example, the following two program fragments are equivalent, and should produce the same token stream except for the line and column positions:
if ( p /* meaning n is prime */ ) {
print ( n , " " ) ;
count = count + 1 ; /* number of primes found so far */
}
if(p){print(n," ");count=count+1;}
Complete list of token names
End_of_input Op_multiply Op_divide Op_mod Op_add Op_subtract
Op_negate Op_not Op_less Op_lessequal Op_greater Op_greaterequal
Op_equal Op_notequal Op_assign Op_and Op_or Keyword_if
Keyword_else Keyword_while Keyword_print Keyword_putc LeftParen RightParen
LeftBrace RightBrace Semicolon Comma Identifier Integer
String
Output Format
The program output should be a sequence of lines, each consisting of the following whitespace-separated fields:
the line number where the token starts
the column number where the token starts
the token name
the token value (only for Identifier, Integer, and String tokens)
the number of spaces between fields is up to you. Neatly aligned is nice, but not a requirement.
This task is intended to be used as part of a pipeline, with the other compiler tasks - for example:
lex < hello.t | parse | gen | vm
Or possibly:
lex hello.t lex.out
parse lex.out parse.out
gen parse.out gen.out
vm gen.out
This implies that the output of this task (the lexical analyzer) should be suitable as input to any of the Syntax Analyzer task programs.
Diagnostics
The following error conditions should be caught:
Error
Example
Empty character constant
''
Unknown escape sequence.
\r
Multi-character constant.
'xx'
End-of-file in comment. Closing comment characters not found.
End-of-file while scanning string literal. Closing string character not found.
End-of-line while scanning string literal. Closing string character not found before end-of-line.
Unrecognized character.
|
Invalid number. Starts like a number, but ends in non-numeric characters.
123abc
Test Cases
Input
Output
Test Case 1:
/*
Hello world
*/
print("Hello, World!\n");
4 1 Keyword_print
4 6 LeftParen
4 7 String "Hello, World!\n"
4 24 RightParen
4 25 Semicolon
5 1 End_of_input
Test Case 2:
/*
Show Ident and Integers
*/
phoenix_number = 142857;
print(phoenix_number, "\n");
4 1 Identifier phoenix_number
4 16 Op_assign
4 18 Integer 142857
4 24 Semicolon
5 1 Keyword_print
5 6 LeftParen
5 7 Identifier phoenix_number
5 21 Comma
5 23 String "\n"
5 27 RightParen
5 28 Semicolon
6 1 End_of_input
Test Case 3:
/*
All lexical tokens - not syntactically correct, but that will
have to wait until syntax analysis
*/
/* Print */ print /* Sub */ -
/* Putc */ putc /* Lss */ <
/* If */ if /* Gtr */ >
/* Else */ else /* Leq */ <=
/* While */ while /* Geq */ >=
/* Lbrace */ { /* Eq */ ==
/* Rbrace */ } /* Neq */ !=
/* Lparen */ ( /* And */ &&
/* Rparen */ ) /* Or */ ||
/* Uminus */ - /* Semi */ ;
/* Not */ ! /* Comma */ ,
/* Mul */ * /* Assign */ =
/* Div */ / /* Integer */ 42
/* Mod */ % /* String */ "String literal"
/* Add */ + /* Ident */ variable_name
/* character literal */ '\n'
/* character literal */ '\\'
/* character literal */ ' '
5 16 Keyword_print
5 40 Op_subtract
6 16 Keyword_putc
6 40 Op_less
7 16 Keyword_if
7 40 Op_greater
8 16 Keyword_else
8 40 Op_lessequal
9 16 Keyword_while
9 40 Op_greaterequal
10 16 LeftBrace
10 40 Op_equal
11 16 RightBrace
11 40 Op_notequal
12 16 LeftParen
12 40 Op_and
13 16 RightParen
13 40 Op_or
14 16 Op_subtract
14 40 Semicolon
15 16 Op_not
15 40 Comma
16 16 Op_multiply
16 40 Op_assign
17 16 Op_divide
17 40 Integer 42
18 16 Op_mod
18 40 String "String literal"
19 16 Op_add
19 40 Identifier variable_name
20 26 Integer 10
21 26 Integer 92
22 26 Integer 32
23 1 End_of_input
Test Case 4:
/*** test printing, embedded \n and comments with lots of '*' ***/
print(42);
print("\nHello World\nGood Bye\nok\n");
print("Print a slash n - \\n.\n");
2 1 Keyword_print
2 6 LeftParen
2 7 Integer 42
2 9 RightParen
2 10 Semicolon
3 1 Keyword_print
3 6 LeftParen
3 7 String "\nHello World\nGood Bye\nok\n"
3 38 RightParen
3 39 Semicolon
4 1 Keyword_print
4 6 LeftParen
4 7 String "Print a slash n - \\n.\n"
4 33 RightParen
4 34 Semicolon
5 1 End_of_input
Additional examples
Your solution should pass all the test cases above and the additional tests found Here.
Reference
The C and Python versions can be considered reference implementations.
Related Tasks
Syntax Analyzer task
Code Generator task
Virtual Machine Interpreter task
AST Interpreter task
| #RATFOR | RATFOR | ######################################################################
#
# The Rosetta Code scanner in Ratfor 77.
#
#
# How to deal with FORTRAN 77 input is a problem. I use formatted
# input, treating each line as an array of type CHARACTER--regrettably
# of no more than some predetermined, finite length. It is a very
# simple method and presents no significant difficulties, aside from
# the restriction on line length of the input.
#
#
# On a POSIX platform, the program can be compiled with f2c and run
# somewhat as follows:
#
# ratfor77 lex-in-ratfor.r > lex-in-ratfor.f
# f2c -C -Nc40 lex-in-ratfor.f
# cc -O lex-in-ratfor.c -lf2c
# ./a.out < compiler-tests/primes.t
#
# With gfortran, a little differently:
#
# ratfor77 lex-in-ratfor.r > lex-in-ratfor.f
# gfortran -O2 -fcheck=all -std=legacy lex-in-ratfor.f
# ./a.out < compiler-tests/primes.t
#
#
# I/O is strictly from default input and to default output, which, on
# POSIX systems, usually correspond respectively to standard input and
# standard output. (I did not wish to have to deal with unit numbers;
# these are now standardized in ISO_FORTRAN_ENV, but that is not
# available in FORTRAN 77.)
#
#---------------------------------------------------------------------
# Some parameters you may with to modify.
define(LINESZ, 256) # Size of an input line.
define(OUTLSZ, 512) # Size of an output line.
define(PSHBSZ, 10) # Size of the character pushback buffer.
define(STRNSZ, 4096) # Size of the string pool.
#---------------------------------------------------------------------
define(EOF, -1)
define(NEWLIN, 10) # Unix newline (the LF control character).
define(BACKSL, 92) # ASCII backslash.
define(ILINNO, 1) # Line number's index.
define(ICOLNO, 2) # Column number's index.
define(CHRSZ, 3) # See ILINNO and ICOLNO above.
define(ICHRCD, 3) # Character code's index.
define(TOKSZ, 5) # See ILINNO and ICOLNO above.
define(ITOKNO, 3) # Token number's index.
define(IARGIX, 4) # Index of the string pool index.
define(IARGLN, 5) # Index of the string length.
define(TKELSE, 0)
define(TKIF, 1)
define(TKPRNT, 2)
define(TKPUTC, 3)
define(TKWHIL, 4)
define(TKMUL, 5)
define(TKDIV, 6)
define(TKMOD, 7)
define(TKADD, 8)
define(TKSUB, 9)
define(TKNEG, 10)
define(TKLT, 11)
define(TKLE, 12)
define(TKGT, 13)
define(TKGE, 14)
define(TKEQ, 15)
define(TKNE, 16)
define(TKNOT, 17)
define(TKASGN, 18)
define(TKAND, 19)
define(TKOR, 20)
define(TKLPAR, 21)
define(TKRPAR, 22)
define(TKLBRC, 23)
define(TKRBRC, 24)
define(TKSEMI, 25)
define(TKCMMA, 26)
define(TKID, 27)
define(TKINT, 28)
define(TKSTR, 29)
define(TKEOI, 30)
define(LOC10, 1) # Location of "10" in the string pool.
define(LOC92, 3) # Location of "92" in the string pool.
#---------------------------------------------------------------------
subroutine addstr (strngs, istrng, src, i0, n0, i, n)
# Add a string to the string pool.
implicit none
character strngs(STRNSZ) # String pool.
integer istrng # String pool's next slot.
character src(*) # Source string.
integer i0, n0 # Index and length in source string.
integer i, n # Index and length in string pool.
integer j
if (STRNSZ < istrng + (n0 - 1))
{
write (*, '(''string pool exhausted'')')
stop
}
for (j = 0; j < n0; j = j + 1)
strngs(istrng + j) = src(i0 + j)
i = istrng
n = n0
istrng = istrng + n0
end
subroutine cpystr (strngs, i, n, dst, i0)
# Copy a string from the string pool to an output string.
implicit none
character strngs(STRNSZ) # String pool.
integer i, n # Index and length in string pool.
character dst(OUTLSZ) # Destination string.
integer i0 # Index within destination string.
integer j
if (i0 < 1 || OUTLSZ < i0 + (n - 1))
{
write (*, '(''string boundary exceeded'')')
stop
}
for (j = 0; j < n; j = j + 1)
dst(i0 + j) = strngs(i + j)
end
#---------------------------------------------------------------------
subroutine getchr (line, linno, colno, pushbk, npshbk, chr)
# Get a character, with its line number and column number.
implicit none
character line(LINESZ) # Input buffer.
integer linno, colno # Current line and column numbers.
integer pushbk(CHRSZ, PSHBSZ) # Pushback buffer.
integer npshbk # Number of characters pushed back.
integer chr(CHRSZ)
# End of file is indicated (as in C) by a negative "char code"
# called "EOF".
character*20 fmt
integer stat
integer chr1(CHRSZ)
if (0 < npshbk)
{
chr(ICHRCD) = pushbk(ICHRCD, npshbk)
chr(ILINNO) = pushbk(ILINNO, npshbk)
chr(ICOLNO) = pushbk(ICOLNO, npshbk)
npshbk = npshbk - 1
}
else if (colno <= LINESZ)
{
chr(ICHRCD) = ichar (line(colno))
chr(ILINNO) = linno
chr(ICOLNO) = colno
colno = colno + 1
}
else
{
# Return a newline character.
chr(ICHRCD) = NEWLIN
chr(ILINNO) = linno
chr(ICOLNO) = colno
# Fetch a new line.
linno = linno + 1
colno = 1
# Read a line of text as an array of characters.
write (fmt, '(''('', I10, ''A1)'')') LINESZ
read (*, fmt, iostat = stat) line
if (stat != 0)
{
# If end of file has been reached, push an EOF.
chr1(ICHRCD) = EOF
chr1(ILINNO) = linno
chr1(ICOLNO) = colno
call pshchr (pushbk, npshbk, chr1)
}
}
end
subroutine pshchr (pushbk, npshbk, chr)
# Push back a character.
implicit none
integer pushbk(CHRSZ, PSHBSZ) # Pushback buffer.
integer npshbk # Number of characters pushed back.
integer chr(CHRSZ)
if (PSHBSZ <= npshbk)
{
write (*, '(''pushback buffer overfull'')')
stop
}
npshbk = npshbk + 1
pushbk(ICHRCD, npshbk) = chr(ICHRCD)
pushbk(ILINNO, npshbk) = chr(ILINNO)
pushbk(ICOLNO, npshbk) = chr(ICOLNO)
end
subroutine getpos (line, linno, colno, pushbk, npshbk, ln, cn)
# Get the position of the next character.
implicit none
character line(LINESZ) # Input buffer.
integer linno, colno # Current line and column numbers.
integer pushbk(CHRSZ, PSHBSZ) # Pushback buffer.
integer npshbk # Number of characters pushed back.
integer ln, cn # The line and column nos. returned.
integer chr(CHRSZ)
call getchr (line, linno, colno, pushbk, npshbk, chr)
ln = chr(ILINNO)
cn = chr(ICOLNO)
call pshchr (pushbk, npshbk, chr)
end
#---------------------------------------------------------------------
function isspc (c)
# Is c character code for a space?
implicit none
integer c
logical isspc
#
# The following is correct for ASCII: 32 is the SPACE character, and
# 9 to 13 are control characters commonly regarded as spaces.
#
# In Unicode these are all code points for spaces, but so are others
# besides.
#
isspc = (c == 32 || (9 <= c && c <= 13))
end
function isdgt (c)
# Is c character code for a digit?
implicit none
integer c
logical isdgt
isdgt = (ichar ('0') <= c && c <= ichar ('9'))
end
function isalph (c)
# Is c character code for a letter?
implicit none
integer c
logical isalph
#
# The following is correct for ASCII and Unicode, but not for
# EBCDIC.
#
isalph = (ichar ('a') <= c && c <= ichar ('z')) _
|| (ichar ('A') <= c && c <= ichar ('Z'))
end
function isid0 (c)
# Is c character code for the start of an identifier?
implicit none
integer c
logical isid0
logical isalph
isid0 = isalph (c) || c == ichar ('_')
end
function isid1 (c)
# Is c character code for the continuation of an identifier?
implicit none
integer c
logical isid1
logical isalph
logical isdgt
isid1 = isalph (c) || isdgt (c) || c == ichar ('_')
end
#---------------------------------------------------------------------
function trimlf (str, n)
# "Trim left" leading spaces.
implicit none
character str(*) # The string to "trim".
integer n # The length.
integer trimlf # The index of the first non-space
# character, or n + 1.
logical isspc
integer j
logical done
j = 1
done = .false.
while (!done)
{
if (j == n + 1)
done = .true.
else if (!isspc (ichar (str(j))))
done = .true.
else
j = j + 1
}
trimlf = j
end
function trimrt (str, n)
# "Trim right" trailing spaces.
implicit none
character str(*) # The string to "trim".
integer n # The length including trailing spaces.
integer trimrt # The length without trailing spaces.
logical isspc
integer j
logical done
j = n
done = .false.
while (!done)
{
if (j == 0)
done = .true.
else if (!isspc (ichar (str(j))))
done = .true.
else
j = j - 1
}
trimrt = j
end
#---------------------------------------------------------------------
subroutine toknam (tokno, str, i)
# Copy a token name to the character array str, starting at i.
implicit none
integer tokno
character str(*)
integer i
integer j
character*16 names(0:30)
character*16 nm
data names / "Keyword_else ", _
"Keyword_if ", _
"Keyword_print ", _
"Keyword_putc ", _
"Keyword_while ", _
"Op_multiply ", _
"Op_divide ", _
"Op_mod ", _
"Op_add ", _
"Op_subtract ", _
"Op_negate ", _
"Op_less ", _
"Op_lessequal ", _
"Op_greater ", _
"Op_greaterequal ", _
"Op_equal ", _
"Op_notequal ", _
"Op_not ", _
"Op_assign ", _
"Op_and ", _
"Op_or ", _
"LeftParen ", _
"RightParen ", _
"LeftBrace ", _
"RightBrace ", _
"Semicolon ", _
"Comma ", _
"Identifier ", _
"Integer ", _
"String ", _
"End_of_input " /
nm = names(tokno)
for (j = 0; j < 16; j = j + 1)
str(i + j) = nm(1 + j : 1 + j)
end
subroutine intstr (str, i, n, x)
# Convert a positive integer to a substring.
implicit none
character str(*) # Destination string.
integer i, n # Index and length of the field.
integer x # The positive integer to represent.
integer j
integer y
if (x == 0)
{
for (j = 0; j < n - 1; j = j + 1)
str(i + j) = ' '
str(i + j) = '0'
}
else
{
y = x
for (j = n - 1; 0 <= j; j = j - 1)
{
if (y == 0)
str(i + j) = ' '
else
{
str(i + j) = char (mod (y, 10) + ichar ('0'))
y = y / 10
}
}
}
end
subroutine prttok (strngs, tok)
# Print a token.
implicit none
character strngs(STRNSZ) # String pool.
integer tok(TOKSZ) # The token.
integer trimrt
character line(OUTLSZ)
character*20 fmt
integer i, n
integer tokno
for (i = 1; i <= OUTLSZ; i = i + 1)
line(i) = ' '
call intstr (line, 1, 10, tok(ILINNO))
call intstr (line, 12, 10, tok(ICOLNO))
tokno = tok(ITOKNO)
call toknam (tokno, line, 25)
if (tokno == TKID || tokno == TKINT || tokno == TKSTR)
{
i = tok(IARGIX)
n = tok(IARGLN)
call cpystr (strngs, i, n, line, 45)
}
n = trimrt (line, OUTLSZ)
write (fmt, '(''('', I10, ''A)'')') n
write (*, fmt) (line(i), i = 1, n)
end
#---------------------------------------------------------------------
subroutine wrtpos (ln, cn)
implicit none
integer ln, cn
write (*, 1000) ln, cn
1000 format ('At line ', I5, ', column ' I5)
end
#---------------------------------------------------------------------
subroutine utcmnt (ln, cn)
implicit none
integer ln, cn
call wrtpos (ln, cn)
write (*, '(''Unterminated comment'')')
stop
end
subroutine skpcmt (line, linno, colno, pushbk, npshbk, ln, cn)
# Skip to the end of a comment.
implicit none
character line(LINESZ) # Input buffer.
integer linno, colno # Current line and column numbers.
integer pushbk(CHRSZ, PSHBSZ) # Pushback buffer.
integer npshbk # Number of characters pushed back.
integer ln, cn # Line and column of start of comment.
integer chr(CHRSZ)
logical done
done = .false.
while (!done)
{
call getchr (line, linno, colno, pushbk, npshbk, chr)
if (chr(ICHRCD) == ichar ('*'))
{
call getchr (line, linno, colno, pushbk, npshbk, chr)
if (chr(ICHRCD) == ichar ('/'))
done = .true.
else if (chr(ICHRCD) == EOF)
call utcmnt (ln, cn)
}
else if (chr(ICHRCD) == EOF)
call utcmnt (ln, cn)
}
end
subroutine skpspc (line, linno, colno, pushbk, npshbk)
# Skip spaces and comments.
implicit none
character line(LINESZ) # Input buffer.
integer linno, colno # Current line and column numbers.
integer pushbk(CHRSZ, PSHBSZ) # Pushback buffer.
integer npshbk # Number of characters pushed back.
logical isspc
integer chr(CHRSZ)
integer chr1(CHRSZ)
integer ln, cn
logical done
done = .false.
while (!done)
{
call getchr (line, linno, colno, pushbk, npshbk, chr)
if (!isspc (chr(ICHRCD)))
{
if (chr(ICHRCD) != ichar ('/'))
{
call pshchr (pushbk, npshbk, chr)
done = .true.
}
else
{
call getchr (line, linno, colno, pushbk, npshbk, chr1)
if (chr1(ICHRCD) != ichar ('*'))
{
call pshchr (pushbk, npshbk, chr1)
call pshchr (pushbk, npshbk, chr)
done = .true.
}
else
{
ln = chr(ILINNO)
cn = chr(ICOLNO)
call skpcmt (line, linno, colno, pushbk, npshbk, _
ln, cn)
}
}
}
}
end
#---------------------------------------------------------------------
subroutine rwdlkp (strngs, istrng, src, i0, n0, ln, cn, tok)
# Reserved word lookup
implicit none
character strngs(STRNSZ) # String pool.
integer istrng # String pool's next slot.
character src(*) # The source string.
integer i0, n0 # Index and length of the substring.
integer ln, cn # Line and column number
# to associate with the token.
integer tok(TOKSZ) # The output token.
integer tokno
integer i, n
tokno = TKID
if (n0 == 2)
{
if (src(i0) == 'i' && src(i0 + 1) == 'f')
tokno = TKIF
}
else if (n0 == 4)
{
if (src(i0) == 'e' && src(i0 + 1) == 'l' _
&& src(i0 + 2) == 's' && src(i0 + 3) == 'e')
tokno = TKELSE
else if (src(i0) == 'p' && src(i0 + 1) == 'u' _
&& src(i0 + 2) == 't' && src(i0 + 3) == 'c')
tokno = TKPUTC
}
else if (n0 == 5)
{
if (src(i0) == 'p' && src(i0 + 1) == 'r' _
&& src(i0 + 2) == 'i' && src(i0 + 3) == 'n' _
&& src(i0 + 4) == 't')
tokno = TKPRNT
else if (src(i0) == 'w' && src(i0 + 1) == 'h' _
&& src(i0 + 2) == 'i' && src(i0 + 3) == 'l' _
&& src(i0 + 4) == 'e')
tokno = TKWHIL
}
i = 0
n = 0
if (tokno == TKID)
call addstr (strngs, istrng, src, i0, n0, i, n)
tok(ITOKNO) = tokno
tok(IARGIX) = i
tok(IARGLN) = n
tok(ILINNO) = ln
tok(ICOLNO) = cn
end
subroutine scnwrd (line, linno, colno, pushbk, npshbk, ln, cn, buf, n)
# Scan characters that may represent an identifier, reserved word,
# or integer literal.
implicit none
character line(LINESZ) # Input buffer.
integer linno, colno # Current line and column numbers.
integer pushbk(CHRSZ, PSHBSZ) # Pushback buffer.
integer npshbk # Number of characters pushed back.
integer ln, cn # Line and column number of the start.
character buf(LINESZ) # The output buffer.
integer n # The length of the string collected.
logical isid1
integer chr(CHRSZ)
n = 0
call getchr (line, linno, colno, pushbk, npshbk, chr)
ln = chr(ILINNO)
cn = chr(ICOLNO)
while (isid1 (chr(ICHRCD)))
{
n = n + 1
buf(n) = char (chr(ICHRCD))
call getchr (line, linno, colno, pushbk, npshbk, chr)
}
call pshchr (pushbk, npshbk, chr)
end
subroutine scnidr (strngs, istrng, _
line, linno, colno, pushbk, npshbk, _
tok)
# Scan an identifier or reserved word.
implicit none
character strngs(STRNSZ) # String pool.
integer istrng # String pool's next slot.
character line(LINESZ) # Input buffer.
integer linno, colno # Current line and column numbers.
integer pushbk(CHRSZ, PSHBSZ) # Pushback buffer.
integer npshbk # Number of characters pushed back.
integer ln, cn # Line and column number of the start.
integer tok(TOKSZ) # The output token.
character buf(LINESZ)
integer n
call scnwrd (line, linno, colno, pushbk, npshbk, ln, cn, buf, n)
call rwdlkp (strngs, istrng, buf, 1, n, ln, cn, tok)
end
subroutine scnint (strngs, istrng, _
line, linno, colno, pushbk, npshbk, _
tok)
# Scan a positive integer literal.
implicit none
character strngs(STRNSZ) # String pool.
integer istrng # String pool's next slot.
character line(LINESZ) # Input buffer.
integer linno, colno # Current line and column numbers.
integer pushbk(CHRSZ, PSHBSZ) # Pushback buffer.
integer npshbk # Number of characters pushed back.
integer ln, cn # Line and column number of the start.
integer tok(TOKSZ) # The output token.
logical isdgt
character buf(LINESZ)
integer n0, n
integer i, j, k
character*80 fmt
call scnwrd (line, linno, colno, pushbk, npshbk, ln, cn, buf, n0)
for (j = 1; j <= n0; j = j + 1)
if (!isdgt (ichar (buf(j))))
{
call wrtpos (ln, cn)
write (fmt, 1000) n0
1000 format ('(''Not a legal word: "''', I10, 'A, ''"'')')
write (*, fmt) (buf(k), k = 1, n0)
stop
}
call addstr (strngs, istrng, buf, 1, n0, i, n)
tok(ITOKNO) = TKINT
tok(IARGIX) = i
tok(IARGLN) = n
tok(ILINNO) = ln
tok(ICOLNO) = cn
end
subroutine utclit (ln, cn)
implicit none
integer ln, cn
call wrtpos (ln, cn)
write (*, '(''Unterminated character literal'')')
stop
end
subroutine scnch1 (strngs, istrng, _
line, linno, colno, pushbk, npshbk, _
tok)
# Scan a character literal, without yet checking that the literal
# ends correctly.
implicit none
character strngs(STRNSZ) # String pool.
integer istrng # String pool's next slot.
character line(LINESZ) # Input buffer.
integer linno, colno # Current line and column numbers.
integer pushbk(CHRSZ, PSHBSZ) # Pushback buffer.
integer npshbk # Number of characters pushed back.
integer tok(TOKSZ) # The output token.
integer trimlf
integer bufsz
parameter (bufsz = 40)
integer chr(CHRSZ)
integer chr1(CHRSZ)
integer chr2(CHRSZ)
integer ln, cn
character buf(bufsz)
integer i, j, n
# Refetch the opening quote.
call getchr (line, linno, colno, pushbk, npshbk, chr)
ln = chr(ILINNO)
cn = chr(ICOLNO)
tok(ITOKNO) = TKINT
tok(ILINNO) = ln
tok(ICOLNO) = cn
call getchr (line, linno, colno, pushbk, npshbk, chr1)
if (chr1(ICHRCD) == EOF)
call utclit (ln, cn)
if (chr1(ICHRCD) == BACKSL)
{
call getchr (line, linno, colno, pushbk, npshbk, chr2)
if (chr2(ICHRCD) == EOF)
call utclit (ln, cn)
else if (chr2(ICHRCD) == ichar ('n'))
{
tok(IARGIX) = LOC10 # "10" = code for Unix newline
tok(IARGLN) = 2
}
else if (chr2(ICHRCD) == BACKSL)
{
tok(IARGIX) = LOC92 # "92" = code for backslash
tok(IARGLN) = 2
}
else
{
call wrtpos (ln, cn)
write (*, '(''Unsupported escape: '', 1A)') _
char (chr2(ICHRCD))
stop
}
}
else
{
# Character codes are non-negative, so we can use intstr.
call intstr (buf, 1, bufsz, chr1(ICHRCD))
j = trimlf (buf, bufsz)
call addstr (strngs, istrng, buf, j, bufsz - (j - 1), i, n)
tok(IARGIX) = i
tok(IARGLN) = n
}
end
subroutine scnch (strngs, istrng, _
line, linno, colno, pushbk, npshbk, _
tok)
# Scan a character literal.
implicit none
character strngs(STRNSZ) # String pool.
integer istrng # String pool's next slot.
character line(LINESZ) # Input buffer.
integer linno, colno # Current line and column numbers.
integer pushbk(CHRSZ, PSHBSZ) # Pushback buffer.
integer npshbk # Number of characters pushed back.
integer tok(TOKSZ) # The output token.
integer ln, cn
integer chr(CHRSZ)
call getpos (line, linno, colno, pushbk, npshbk, ln, cn)
call scnch1 (strngs, istrng, _
line, linno, colno, pushbk, npshbk, _
tok)
call getchr (line, linno, colno, pushbk, npshbk, chr)
if (chr(ICHRCD) != ichar (''''))
{
while (.true.)
{
if (chr(ICHRCD) == EOF)
{
call utclit (ln, cn)
stop
}
else if (chr(ICHRCD) == ichar (''''))
{
call wrtpos (ln, cn)
write (*, '(''Unsupported multicharacter literal'')')
stop
}
call getchr (line, linno, colno, pushbk, npshbk, chr)
}
}
end
subroutine scnstr (strngs, istrng, _
line, linno, colno, pushbk, npshbk, _
tok)
# Scan a string literal.
implicit none
character strngs(STRNSZ) # String pool.
integer istrng # String pool's next slot.
character line(LINESZ) # Input buffer.
integer linno, colno # Current line and column numbers.
integer pushbk(CHRSZ, PSHBSZ) # Pushback buffer.
integer npshbk # Number of characters pushed back.
integer tok(TOKSZ) # The output token.
integer ln, cn
integer chr1(CHRSZ)
integer chr2(CHRSZ)
character buf(LINESZ + 10) # Enough space, with some room to spare.
integer n0
integer i, n
call getchr (line, linno, colno, pushbk, npshbk, chr1)
ln = chr1(ILINNO)
cn = chr1(ICOLNO)
tok(ITOKNO) = TKSTR
tok(ILINNO) = ln
tok(ICOLNO) = cn
n0 = 1
buf(n0) = '"'
call getchr (line, linno, colno, pushbk, npshbk, chr1)
while (chr1(ICHRCD) != ichar ('"'))
{
# Our input method always puts a NEWLIN before EOF, and so this
# test is redundant, unless someone changes the input method.
if (chr1(ICHRCD) == EOF || chr1(ICHRCD) == NEWLIN)
{
call wrtpos (ln, cn)
write (*, '(''Unterminated string literal'')')
stop
}
if (chr1(ICHRCD) == BACKSL)
{
call getchr (line, linno, colno, pushbk, npshbk, chr2)
if (chr2(ICHRCD) == ichar ('n'))
{
n0 = n0 + 1
buf(n0) = char (BACKSL)
n0 = n0 + 1
buf(n0) = 'n'
}
else if (chr2(ICHRCD) == BACKSL)
{
n0 = n0 + 1
buf(n0) = char (BACKSL)
n0 = n0 + 1
buf(n0) = char (BACKSL)
}
else
{
call wrtpos (chr1(ILINNO), chr1(ICOLNO))
write (*, '(''Unsupported escape sequence'')')
stop
}
}
else
{
n0 = n0 + 1
buf(n0) = char (chr1(ICHRCD))
}
call getchr (line, linno, colno, pushbk, npshbk, chr1)
}
n0 = n0 + 1
buf(n0) = '"'
call addstr (strngs, istrng, buf, 1, n0, i, n)
tok(IARGIX) = i
tok(IARGLN) = n
end
subroutine unxchr (chr)
implicit none
integer chr(CHRSZ)
call wrtpos (chr(ILINNO), chr(ICOLNO))
write (*, 1000) char (chr(ICHRCD))
1000 format ('Unexpected character ''', A1, '''')
stop
end
subroutine scntok (strngs, istrng, _
line, linno, colno, pushbk, npshbk, _
tok)
# Scan a token.
implicit none
character strngs(STRNSZ) # String pool.
integer istrng # String pool's next slot.
character line(LINESZ) # Input buffer.
integer linno, colno # Current line and column numbers.
integer pushbk(CHRSZ, PSHBSZ) # Pushback buffer.
integer npshbk # Number of characters pushed back.
integer tok(TOKSZ) # The output token.
logical isdgt
logical isid0
integer chr(CHRSZ)
integer chr1(CHRSZ)
integer ln, cn
call getchr (line, linno, colno, pushbk, npshbk, chr)
ln = chr(ILINNO)
cn = chr(ICOLNO)
tok(ILINNO) = ln
tok(ICOLNO) = cn
tok(IARGIX) = 0
tok(IARGLN) = 0
if (chr(ICHRCD) == ichar (','))
tok(ITOKNO) = TKCMMA
else if (chr(ICHRCD) == ichar (';'))
tok(ITOKNO) = TKSEMI
else if (chr(ICHRCD) == ichar ('('))
tok(ITOKNO) = TKLPAR
else if (chr(ICHRCD) == ichar (')'))
tok(ITOKNO) = TKRPAR
else if (chr(ICHRCD) == ichar ('{'))
tok(ITOKNO) = TKLBRC
else if (chr(ICHRCD) == ichar ('}'))
tok(ITOKNO) = TKRBRC
else if (chr(ICHRCD) == ichar ('*'))
tok(ITOKNO) = TKMUL
else if (chr(ICHRCD) == ichar ('/'))
tok(ITOKNO) = TKDIV
else if (chr(ICHRCD) == ichar ('%'))
tok(ITOKNO) = TKMOD
else if (chr(ICHRCD) == ichar ('+'))
tok(ITOKNO) = TKADD
else if (chr(ICHRCD) == ichar ('-'))
tok(ITOKNO) = TKSUB
else if (chr(ICHRCD) == ichar ('<'))
{
call getchr (line, linno, colno, pushbk, npshbk, chr1)
if (chr1(ICHRCD) == ichar ('='))
tok(ITOKNO) = TKLE
else
{
call pshchr (pushbk, npshbk, chr1)
tok(ITOKNO) = TKLT
}
}
else if (chr(ICHRCD) == ichar ('>'))
{
call getchr (line, linno, colno, pushbk, npshbk, chr1)
if (chr1(ICHRCD) == ichar ('='))
tok(ITOKNO) = TKGE
else
{
call pshchr (pushbk, npshbk, chr1)
tok(ITOKNO) = TKGT
}
}
else if (chr(ICHRCD) == ichar ('='))
{
call getchr (line, linno, colno, pushbk, npshbk, chr1)
if (chr1(ICHRCD) == ichar ('='))
tok(ITOKNO) = TKEQ
else
{
call pshchr (pushbk, npshbk, chr1)
tok(ITOKNO) = TKASGN
}
}
else if (chr(ICHRCD) == ichar ('!'))
{
call getchr (line, linno, colno, pushbk, npshbk, chr1)
if (chr1(ICHRCD) == ichar ('='))
tok(ITOKNO) = TKNE
else
{
call pshchr (pushbk, npshbk, chr1)
tok(ITOKNO) = TKNOT
}
}
else if (chr(ICHRCD) == ichar ('&'))
{
call getchr (line, linno, colno, pushbk, npshbk, chr1)
if (chr1(ICHRCD) == ichar ('&'))
tok(ITOKNO) = TKAND
else
call unxchr (chr)
}
else if (chr(ICHRCD) == ichar ('|'))
{
call getchr (line, linno, colno, pushbk, npshbk, chr1)
if (chr1(ICHRCD) == ichar ('|'))
tok(ITOKNO) = TKOR
else
call unxchr (chr)
}
else if (chr(ICHRCD) == ichar ('"'))
{
call pshchr (pushbk, npshbk, chr)
call scnstr (strngs, istrng, _
line, linno, colno, pushbk, npshbk, _
tok)
}
else if (chr(ICHRCD) == ichar (''''))
{
call pshchr (pushbk, npshbk, chr)
call scnch (strngs, istrng, _
line, linno, colno, pushbk, npshbk, _
tok)
}
else if (isdgt (chr(ICHRCD)))
{
call pshchr (pushbk, npshbk, chr)
call scnint (strngs, istrng, _
line, linno, colno, pushbk, npshbk, _
tok)
}
else if (isid0 (chr(ICHRCD)))
{
call pshchr (pushbk, npshbk, chr)
call scnidr (strngs, istrng, _
line, linno, colno, pushbk, npshbk, _
tok)
}
else
call unxchr (chr)
end
subroutine scntxt (strngs, istrng, _
line, linno, colno, pushbk, npshbk)
# Scan the text and print the token stream.
implicit none
character strngs(STRNSZ) # String pool.
integer istrng # String pool's next slot.
character line(LINESZ) # Input buffer.
integer linno, colno # Current line and column numbers.
integer pushbk(CHRSZ, PSHBSZ) # Pushback buffer.
integer npshbk # Number of characters pushed back.
integer chr(CHRSZ)
integer tok(TOKSZ)
chr(ICHRCD) = ichar ('x')
while (chr(ICHRCD) != EOF)
{
call skpspc (line, linno, colno, pushbk, npshbk)
call getchr (line, linno, colno, pushbk, npshbk, chr)
if (chr(ICHRCD) != EOF)
{
call pshchr (pushbk, npshbk, chr)
call scntok (strngs, istrng, _
line, linno, colno, pushbk, npshbk, _
tok)
call prttok (strngs, tok)
}
}
tok(ITOKNO) = TKEOI
tok(ILINNO) = chr(ILINNO)
tok(ICOLNO) = chr(ICOLNO)
tok(IARGIX) = 0
tok(IARGLN) = 0
call prttok (strngs, tok)
end
#---------------------------------------------------------------------
program lex
implicit none
character strngs(STRNSZ) # String pool.
integer istrng # String pool's next slot.
character line(LINESZ) # Input buffer.
integer linno, colno # Current line and column numbers.
integer pushbk(CHRSZ, PSHBSZ) # Pushback buffer.
integer npshbk # Number of characters pushed back.
integer i, n
istrng = 1
# Locate "10" (newline) at 1 in the string pool.
line(1) = '1'
line(2) = '0'
call addstr (strngs, istrng, line, 1, 2, i, n)
if (i != 1 && n != 2)
{
write (*, '(''internal error'')')
stop
}
# Locate "92" (backslash) at 3 in the string pool.
line(1) = '9'
line(2) = '2'
call addstr (strngs, istrng, line, 1, 2, i, n)
if (i != 3 && n != 2)
{
write (*, '(''internal error'')')
stop
}
linno = 0
colno = LINESZ + 1 # This will trigger a READ.
npshbk = 0
call scntxt (strngs, istrng, line, linno, colno, pushbk, npshbk)
end
###################################################################### |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Oforth | Oforth | System.Args println |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Oz | Oz | functor
import Application System
define
ArgList = {Application.getArgs plain}
{ForAll ArgList System.showInfo}
{Application.exit 0}
end |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #F.23 | F# | // this comments to the end of the line
(* this comments a region
which can be multi-line *) |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #Factor | Factor | ! Comments starts with "! "
#! Or with "#! "
! and last until the end of the line
USE: multiline
/* The multiline vocabulary implements
C-like multiline comments. */ |
http://rosettacode.org/wiki/Conway%27s_Game_of_Life | Conway's Game of Life | The Game of Life is a cellular automaton devised by the British mathematician John Horton Conway in 1970. It is the best-known example of a cellular automaton.
Conway's game of life is described here:
A cell C is represented by a 1 when alive, or 0 when dead, in an m-by-m (or m×m) square array of cells.
We calculate N - the sum of live cells in C's eight-location neighbourhood, then cell C is alive or dead in the next generation based on the following table:
C N new C
1 0,1 -> 0 # Lonely
1 4,5,6,7,8 -> 0 # Overcrowded
1 2,3 -> 1 # Lives
0 3 -> 1 # It takes three to give birth!
0 0,1,2,4,5,6,7,8 -> 0 # Barren
Assume cells beyond the boundary are always dead.
The "game" is actually a zero-player game, meaning that its evolution is determined by its initial state, needing no input from human players. One interacts with the Game of Life by creating an initial configuration and observing how it evolves.
Task
Although you should test your implementation on more complex examples such as the glider in a larger universe, show the action of the blinker (three adjoining cells in a row all alive), over three generations, in a 3 by 3 grid.
References
Its creator John Conway, explains the game of life. Video from numberphile on youtube.
John Conway Inventing Game of Life - Numberphile video.
Related task
Langton's ant - another well known cellular automaton.
| #M2000_Interpreter | M2000 Interpreter |
Module Life {
Font "courier new"
Form 40, 18
Cls 3,0
Double
Report 2, "Game of Life"
Normal
Cls 5, 2
Const Mx=20, My=10
Dim A(0 to Mx+1, 0 to My+1)=0
Flush
REM Data (2,2),(2,3),(3,3),(4,3),(5,4),(,3,4),(5,3),(6,2),(8,5),(5,8)
Data (5,3)
Data (5,4)
Data (5,5)
generation=1
While not empty
(A, B)=Array
A(A,B)=1
End While
Display()
Do
k$=Key$
If k$=chr$(13) Then exit
A()=@GetNext()
refresh 500
Display()
Until A()#Sum()=0
K$=Key$
Cls, 0
End
Function GetNext()
Local B()
B()=A() ' copy array
Local B=B() ' get a pointer
B*=0 ' make all element zero
Local i, j, tot
For j=1 to My
For i=1 to Mx
tot=-A(i,j)
For k=j-1 to j+1
For m=i-1 to i+1
tot+=A(m, k)
Next
Next
If A(i,j)=1 Then
If tot=2 or tot=3 Then B(i,j)=1
Else.if tot=3 Then
B(i,j)=1
End If
Next
Next
=B()
End Function
Sub Display()
Cursor 0,2
move ! ' move graphic to character cursor
Fill scale.x, scale.y-pos.Y, 1, 5
Print "Generation:";Generation
Generation++
Local i, j
For j=1 to My
Print @(width div 2-Mx div 2);
For i=1 to Mx
Print If$(A(I,J)=1->"■", "□");
Next
Print
Next
Print
Report 2, "Press enter to exit or any other key for Next generation"
End Sub
}
Life
|
http://rosettacode.org/wiki/Conditional_structures | Conditional structures | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
List the conditional structures offered by a programming language. See Wikipedia: conditionals for descriptions.
Common conditional structures include if-then-else and switch.
Less common are arithmetic if, ternary operator and Hash-based conditionals.
Arithmetic if allows tight control over computed gotos, which optimizers have a hard time to figure out.
| #EasyLang | EasyLang | i = random 10
if i mod 2 = 0
print i & " is divisible by 2"
elif i mod 3 = 0
print i & " is divisible by 3"
else
print i & " is not divisible by 2 or 3"
. |
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #Scheme | Scheme |
(define (compare-strings fn strs)
(or (null? strs) ; returns #t on empty list
(null? (cdr strs)) ; returns #t on list of size 1
(do ((fst strs (cdr fst))
(snd (cdr strs) (cdr snd)))
((or (null? snd)
(not (fn (car fst) (car snd))))
(null? snd))))) ; returns #t if the snd list is empty, meaning all comparisons are exhausted
(compare-strings string=? strings) ; test for all equal
(compare-strings string<? strings) ; test for in ascending order
|
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #Seed7 | Seed7 | $ include "seed7_05.s7i";
const func boolean: allTheSame (in array string: strings) is func
result
var boolean: allTheSame is TRUE;
local
var integer: index is 0;
begin
for index range 2 to length(strings) until not allTheSame do
if strings[pred(index)] <> strings[index] then
allTheSame := FALSE;
end if;
end for;
end func;
const func boolean: strictlyAscending (in array string: strings) is func
result
var boolean: strictlyAscending is TRUE;
local
var integer: index is 0;
begin
for index range 2 to length(strings) until not strictlyAscending do
if strings[pred(index)] >= strings[index] then
strictlyAscending := FALSE;
end if;
end for;
end func; |
http://rosettacode.org/wiki/Comma_quibbling | Comma quibbling | Comma quibbling is a task originally set by Eric Lippert in his blog.
Task
Write a function to generate a string output which is the concatenation of input words from a list/sequence where:
An input of no words produces the output string of just the two brace characters "{}".
An input of just one word, e.g. ["ABC"], produces the output string of the word inside the two braces, e.g. "{ABC}".
An input of two words, e.g. ["ABC", "DEF"], produces the output string of the two words inside the two braces with the words separated by the string " and ", e.g. "{ABC and DEF}".
An input of three or more words, e.g. ["ABC", "DEF", "G", "H"], produces the output string of all but the last word separated by ", " with the last word separated by " and " and all within braces; e.g. "{ABC, DEF, G and H}".
Test your function with the following series of inputs showing your output here on this page:
[] # (No input words).
["ABC"]
["ABC", "DEF"]
["ABC", "DEF", "G", "H"]
Note: Assume words are non-empty strings of uppercase characters for this task.
| #MAXScript | MAXScript |
fn separate words: =
(
if words == unsupplied or words == undefined or classof words != array then return "{}"
else
(
local toReturn = "{"
local pos = 1
while pos <= words.count do
(
if pos == 1 then (append toReturn words[pos]; pos+=1)
else
(
if pos <= words.count-1 then (append toReturn (", "+words[pos]); pos+=1)
else
(
append toReturn (" and " + words[pos])
pos +=1
)
)
)
return (toReturn+"}")
)
)
|
http://rosettacode.org/wiki/Comma_quibbling | Comma quibbling | Comma quibbling is a task originally set by Eric Lippert in his blog.
Task
Write a function to generate a string output which is the concatenation of input words from a list/sequence where:
An input of no words produces the output string of just the two brace characters "{}".
An input of just one word, e.g. ["ABC"], produces the output string of the word inside the two braces, e.g. "{ABC}".
An input of two words, e.g. ["ABC", "DEF"], produces the output string of the two words inside the two braces with the words separated by the string " and ", e.g. "{ABC and DEF}".
An input of three or more words, e.g. ["ABC", "DEF", "G", "H"], produces the output string of all but the last word separated by ", " with the last word separated by " and " and all within braces; e.g. "{ABC, DEF, G and H}".
Test your function with the following series of inputs showing your output here on this page:
[] # (No input words).
["ABC"]
["ABC", "DEF"]
["ABC", "DEF", "G", "H"]
Note: Assume words are non-empty strings of uppercase characters for this task.
| #NetRexx | NetRexx | /* NetRexx */
options replace format comments java crossref symbols nobinary
runSample(arg)
return
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
method quibble(arg) public static
parse arg '[' lst ']'
lst = lst.changestr('"', '').space(1)
lc = lst.lastpos(',')
if lc > 0 then
lst = lst.insert('and', lc).overlay(' ', lc)
return '{'lst'}'
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
method runSample(arg) private static
lists = ['[]', - -- {}
'["ABC"]', - -- {ABC}
'["ABC", "DEF"]', - -- {ABC and DEF}
'["ABC", "DEF", "G", "H"]'] -- {ABC, DEF, G and H}
loop lst over lists
say lst.right(30) ':' quibble(lst)
end lst
return
|
http://rosettacode.org/wiki/Combinations_with_repetitions | Combinations with repetitions | The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of those sets is chosen from
S
{\displaystyle S}
.
In the real world, it is about choosing sets where there is a “large” supply of each type of element and where the order of choice does not matter.
For example:
Q: How many ways can a person choose two doughnuts from a store selling three types of doughnut: iced, jam, and plain? (i.e.,
S
{\displaystyle S}
is
{
i
c
e
d
,
j
a
m
,
p
l
a
i
n
}
{\displaystyle \{\mathrm {iced} ,\mathrm {jam} ,\mathrm {plain} \}}
,
|
S
|
=
3
{\displaystyle |S|=3}
, and
k
=
2
{\displaystyle k=2}
.)
A: 6: {iced, iced}; {iced, jam}; {iced, plain}; {jam, jam}; {jam, plain}; {plain, plain}.
Note that both the order of items within a pair, and the order of the pairs given in the answer is not significant; the pairs represent multisets.
Also note that doughnut can also be spelled donut.
Task
Write a function/program/routine/.. to generate all the combinations with repetitions of
n
{\displaystyle n}
types of things taken
k
{\displaystyle k}
at a time and use it to show an answer to the doughnut example above.
For extra credit, use the function to compute and show just the number of ways of choosing three doughnuts from a choice of ten types of doughnut. Do not show the individual choices for this part.
References
k-combination with repetitions
See also
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #Scheme | Scheme | (define (combs-with-rep k lst)
(cond ((= k 0) '(()))
((null? lst) '())
(else
(append
(map
(lambda (x)
(cons (car lst) x))
(combs-with-rep (- k 1) lst))
(combs-with-rep k (cdr lst))))))
(display (combs-with-rep 2 (list "iced" "jam" "plain"))) (newline)
(display (length (combs-with-rep 3 '(1 2 3 4 5 6 7 8 9 10)))) (newline) |
http://rosettacode.org/wiki/Compiler/lexical_analyzer | Compiler/lexical analyzer | Definition from Wikipedia:
Lexical analysis is the process of converting a sequence of characters (such as in a computer program or web page) into a sequence of tokens (strings with an identified "meaning"). A program that performs lexical analysis may be called a lexer, tokenizer, or scanner (though "scanner" is also used to refer to the first stage of a lexer).
Task[edit]
Create a lexical analyzer for the simple programming language specified below. The
program should read input from a file and/or stdin, and write output to a file and/or
stdout. If the language being used has a lexer module/library/class, it would be great
if two versions of the solution are provided: One without the lexer module, and one with.
Input Specification
The simple programming language to be analyzed is more or less a subset of C. It supports the following tokens:
Operators
Name
Common name
Character sequence
Op_multiply
multiply
*
Op_divide
divide
/
Op_mod
mod
%
Op_add
plus
+
Op_subtract
minus
-
Op_negate
unary minus
-
Op_less
less than
<
Op_lessequal
less than or equal
<=
Op_greater
greater than
>
Op_greaterequal
greater than or equal
>=
Op_equal
equal
==
Op_notequal
not equal
!=
Op_not
unary not
!
Op_assign
assignment
=
Op_and
logical and
&&
Op_or
logical or
¦¦
The - token should always be interpreted as Op_subtract by the lexer. Turning some Op_subtract into Op_negate will be the job of the syntax analyzer, which is not part of this task.
Symbols
Name
Common name
Character
LeftParen
left parenthesis
(
RightParen
right parenthesis
)
LeftBrace
left brace
{
RightBrace
right brace
}
Semicolon
semi-colon
;
Comma
comma
,
Keywords
Name
Character sequence
Keyword_if
if
Keyword_else
else
Keyword_while
while
Keyword_print
print
Keyword_putc
putc
Identifiers and literals
These differ from the the previous tokens, in that each occurrence of them has a value associated with it.
Name
Common name
Format description
Format regex
Value
Identifier
identifier
one or more letter/number/underscore characters, but not starting with a number
[_a-zA-Z][_a-zA-Z0-9]*
as is
Integer
integer literal
one or more digits
[0-9]+
as is, interpreted as a number
Integer
char literal
exactly one character (anything except newline or single quote) or one of the allowed escape sequences, enclosed by single quotes
'([^'\n]|\\n|\\\\)'
the ASCII code point number of the character, e.g. 65 for 'A' and 10 for '\n'
String
string literal
zero or more characters (anything except newline or double quote), enclosed by double quotes
"[^"\n]*"
the characters without the double quotes and with escape sequences converted
For char and string literals, the \n escape sequence is supported to represent a new-line character.
For char and string literals, to represent a backslash, use \\.
No other special sequences are supported. This means that:
Char literals cannot represent a single quote character (value 39).
String literals cannot represent strings containing double quote characters.
Zero-width tokens
Name
Location
End_of_input
when the end of the input stream is reached
White space
Zero or more whitespace characters, or comments enclosed in /* ... */, are allowed between any two tokens, with the exceptions noted below.
"Longest token matching" is used to resolve conflicts (e.g., in order to match <= as a single token rather than the two tokens < and =).
Whitespace is required between two tokens that have an alphanumeric character or underscore at the edge.
This means: keywords, identifiers, and integer literals.
e.g. ifprint is recognized as an identifier, instead of the keywords if and print.
e.g. 42fred is invalid, and neither recognized as a number nor an identifier.
Whitespace is not allowed inside of tokens (except for chars and strings where they are part of the value).
e.g. & & is invalid, and not interpreted as the && operator.
For example, the following two program fragments are equivalent, and should produce the same token stream except for the line and column positions:
if ( p /* meaning n is prime */ ) {
print ( n , " " ) ;
count = count + 1 ; /* number of primes found so far */
}
if(p){print(n," ");count=count+1;}
Complete list of token names
End_of_input Op_multiply Op_divide Op_mod Op_add Op_subtract
Op_negate Op_not Op_less Op_lessequal Op_greater Op_greaterequal
Op_equal Op_notequal Op_assign Op_and Op_or Keyword_if
Keyword_else Keyword_while Keyword_print Keyword_putc LeftParen RightParen
LeftBrace RightBrace Semicolon Comma Identifier Integer
String
Output Format
The program output should be a sequence of lines, each consisting of the following whitespace-separated fields:
the line number where the token starts
the column number where the token starts
the token name
the token value (only for Identifier, Integer, and String tokens)
the number of spaces between fields is up to you. Neatly aligned is nice, but not a requirement.
This task is intended to be used as part of a pipeline, with the other compiler tasks - for example:
lex < hello.t | parse | gen | vm
Or possibly:
lex hello.t lex.out
parse lex.out parse.out
gen parse.out gen.out
vm gen.out
This implies that the output of this task (the lexical analyzer) should be suitable as input to any of the Syntax Analyzer task programs.
Diagnostics
The following error conditions should be caught:
Error
Example
Empty character constant
''
Unknown escape sequence.
\r
Multi-character constant.
'xx'
End-of-file in comment. Closing comment characters not found.
End-of-file while scanning string literal. Closing string character not found.
End-of-line while scanning string literal. Closing string character not found before end-of-line.
Unrecognized character.
|
Invalid number. Starts like a number, but ends in non-numeric characters.
123abc
Test Cases
Input
Output
Test Case 1:
/*
Hello world
*/
print("Hello, World!\n");
4 1 Keyword_print
4 6 LeftParen
4 7 String "Hello, World!\n"
4 24 RightParen
4 25 Semicolon
5 1 End_of_input
Test Case 2:
/*
Show Ident and Integers
*/
phoenix_number = 142857;
print(phoenix_number, "\n");
4 1 Identifier phoenix_number
4 16 Op_assign
4 18 Integer 142857
4 24 Semicolon
5 1 Keyword_print
5 6 LeftParen
5 7 Identifier phoenix_number
5 21 Comma
5 23 String "\n"
5 27 RightParen
5 28 Semicolon
6 1 End_of_input
Test Case 3:
/*
All lexical tokens - not syntactically correct, but that will
have to wait until syntax analysis
*/
/* Print */ print /* Sub */ -
/* Putc */ putc /* Lss */ <
/* If */ if /* Gtr */ >
/* Else */ else /* Leq */ <=
/* While */ while /* Geq */ >=
/* Lbrace */ { /* Eq */ ==
/* Rbrace */ } /* Neq */ !=
/* Lparen */ ( /* And */ &&
/* Rparen */ ) /* Or */ ||
/* Uminus */ - /* Semi */ ;
/* Not */ ! /* Comma */ ,
/* Mul */ * /* Assign */ =
/* Div */ / /* Integer */ 42
/* Mod */ % /* String */ "String literal"
/* Add */ + /* Ident */ variable_name
/* character literal */ '\n'
/* character literal */ '\\'
/* character literal */ ' '
5 16 Keyword_print
5 40 Op_subtract
6 16 Keyword_putc
6 40 Op_less
7 16 Keyword_if
7 40 Op_greater
8 16 Keyword_else
8 40 Op_lessequal
9 16 Keyword_while
9 40 Op_greaterequal
10 16 LeftBrace
10 40 Op_equal
11 16 RightBrace
11 40 Op_notequal
12 16 LeftParen
12 40 Op_and
13 16 RightParen
13 40 Op_or
14 16 Op_subtract
14 40 Semicolon
15 16 Op_not
15 40 Comma
16 16 Op_multiply
16 40 Op_assign
17 16 Op_divide
17 40 Integer 42
18 16 Op_mod
18 40 String "String literal"
19 16 Op_add
19 40 Identifier variable_name
20 26 Integer 10
21 26 Integer 92
22 26 Integer 32
23 1 End_of_input
Test Case 4:
/*** test printing, embedded \n and comments with lots of '*' ***/
print(42);
print("\nHello World\nGood Bye\nok\n");
print("Print a slash n - \\n.\n");
2 1 Keyword_print
2 6 LeftParen
2 7 Integer 42
2 9 RightParen
2 10 Semicolon
3 1 Keyword_print
3 6 LeftParen
3 7 String "\nHello World\nGood Bye\nok\n"
3 38 RightParen
3 39 Semicolon
4 1 Keyword_print
4 6 LeftParen
4 7 String "Print a slash n - \\n.\n"
4 33 RightParen
4 34 Semicolon
5 1 End_of_input
Additional examples
Your solution should pass all the test cases above and the additional tests found Here.
Reference
The C and Python versions can be considered reference implementations.
Related Tasks
Syntax Analyzer task
Code Generator task
Virtual Machine Interpreter task
AST Interpreter task
| #Scala | Scala |
package xyz.hyperreal.rosettacodeCompiler
import scala.io.Source
import scala.util.matching.Regex
object LexicalAnalyzer {
private val EOT = '\u0004'
val symbols =
Map(
"*" -> "Op_multiply",
"/" -> "Op_divide",
"%" -> "Op_mod",
"+" -> "Op_add",
"-" -> "Op_minus",
"<" -> "Op_less",
"<=" -> "Op_lessequal",
">" -> "Op_greater",
">=" -> "Op_greaterequal",
"==" -> "Op_equal",
"!=" -> "Op_notequal",
"!" -> "Op_not",
"=" -> "Op_assign",
"&&" -> "Op_and",
"¦¦" -> "Op_or",
"(" -> "LeftParen",
")" -> "RightParen",
"{" -> "LeftBrace",
"}" -> "RightBrace",
";" -> "Semicolon",
"," -> "Comma"
)
val keywords =
Map(
"if" -> "Keyword_if",
"else" -> "Keyword_else",
"while" -> "Keyword_while",
"print" -> "Keyword_print",
"putc" -> "Keyword_putc"
)
val alpha = ('a' to 'z' toSet) ++ ('A' to 'Z')
val numeric = '0' to '9' toSet
val alphanumeric = alpha ++ numeric
val identifiers = StartRestToken("Identifier", alpha + '_', alphanumeric + '_')
val integers = SimpleToken("Integer", numeric, alpha, "alpha characters may not follow right after a number")
val characters =
DelimitedToken("Integer",
'\'',
"[^'\\n]|\\\\n|\\\\\\\\" r,
"invalid character literal",
"unclosed character literal")
val strings =
DelimitedToken("String", '"', "[^\"\\n]*" r, "invalid string literal", "unclosed string literal")
def apply =
new LexicalAnalyzer(4, symbols, keywords, "End_of_input", identifiers, integers, characters, strings)
abstract class Token
case class StartRestToken(name: String, start: Set[Char], rest: Set[Char]) extends Token
case class SimpleToken(name: String, chars: Set[Char], exclude: Set[Char], excludeError: String) extends Token
case class DelimitedToken(name: String, delimiter: Char, pattern: Regex, patternError: String, unclosedError: String)
extends Token
}
class LexicalAnalyzer(tabs: Int,
symbols: Map[String, String],
keywords: Map[String, String],
endOfInput: String,
identifier: LexicalAnalyzer.Token,
tokens: LexicalAnalyzer.Token*) {
import LexicalAnalyzer._
private val symbolStartChars = symbols.keys map (_.head) toSet
private val symbolChars = symbols.keys flatMap (_.toList) toSet
private var curline: Int = _
private var curcol: Int = _
def fromStdin = fromSource(Source.stdin)
def fromString(src: String) = fromSource(Source.fromString(src))
def fromSource(ast: Source) = {
curline = 1
curcol = 1
var s = (ast ++ Iterator(EOT)) map (new Chr(_)) toStream
tokenize
def token(name: String, first: Chr) = println(f"${first.line}%5d ${first.col}%6d $name")
def value(name: String, v: String, first: Chr) = println(f"${first.line}%5d ${first.col}%6d $name%-14s $v")
def until(c: Char) = {
val buf = new StringBuilder
def until: String =
if (s.head.c == EOT || s.head.c == c)
buf.toString
else {
buf += getch
until
}
until
}
def next = s = s.tail
def getch = {
val c = s.head.c
next
c
}
def consume(first: Char, cs: Set[Char]) = {
val buf = new StringBuilder
def consume: String =
if (s.head.c == EOT || !cs(s.head.c))
buf.toString
else {
buf += getch
consume
}
buf += first
consume
}
def comment(start: Chr): Unit = {
until('*')
if (s.head.c == EOT || s.tail.head.c == EOT)
sys.error(s"unclosed comment ${start.at}")
else if (s.tail.head.c != '/') {
next
comment(start)
} else {
next
next
}
}
def recognize(t: Token): Option[(String, String)] = {
val first = s
next
t match {
case StartRestToken(name, start, rest) =>
if (start(first.head.c))
Some((name, consume(first.head.c, rest)))
else {
s = first
None
}
case SimpleToken(name, chars, exclude, excludeError) =>
if (chars(first.head.c)) {
val m = consume(first.head.c, chars)
if (exclude(s.head.c))
sys.error(s"$excludeError ${s.head.at}")
else
Some((name, m))
} else {
s = first
None
}
case DelimitedToken(name, delimiter, pattern, patternError, unclosedError) =>
if (first.head.c == delimiter) {
val m = until(delimiter)
if (s.head.c != delimiter)
sys.error(s"$unclosedError ${first.head.at}")
else if (pattern.pattern.matcher(m).matches) {
next
Some((name, s"$delimiter$m$delimiter"))
} else
sys.error(s"$patternError ${s.head.at}")
} else {
s = first
None
}
}
}
def tokenize: Unit =
if (s.head.c == EOT)
token(endOfInput, s.head)
else {
if (s.head.c.isWhitespace)
next
else if (s.head.c == '/' && s.tail.head.c == '*')
comment(s.head)
else if (symbolStartChars(s.head.c)) {
val first = s.head
val buf = new StringBuilder
while (!symbols.contains(buf.toString) && s.head.c != EOT && symbolChars(s.head.c)) buf += getch
while (symbols.contains(buf.toString :+ s.head.c) && s.head.c != EOT && symbolChars(s.head.c)) buf += getch
symbols get buf.toString match {
case Some(name) => token(name, first)
case None => sys.error(s"unrecognized symbol: '${buf.toString}' ${first.at}")
}
} else {
val first = s.head
recognize(identifier) match {
case None =>
find(0)
@scala.annotation.tailrec
def find(t: Int): Unit =
if (t == tokens.length)
sys.error(s"unrecognized character ${first.at}")
else
recognize(tokens(t)) match {
case None => find(t + 1)
case Some((name, v)) => value(name, v, first)
}
case Some((name, ident)) =>
keywords get ident match {
case None => value(name, ident, first)
case Some(keyword) => token(keyword, first)
}
}
}
tokenize
}
}
private class Chr(val c: Char) {
val line = curline
val col = curcol
if (c == '\n') {
curline += 1
curcol = 1
} else if (c == '\r')
curcol = 1
else if (c == '\t')
curcol += tabs - (curcol - 1) % tabs
else
curcol += 1
def at = s"[${line}, ${col}]"
override def toString: String = s"<$c, $line, $col>"
}
}
|
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Pascal | Pascal | my @params = @ARGV;
my $params_size = @ARGV;
my $second = $ARGV[1];
my $fifth = $ARGV[4]; |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Perl | Perl | my @params = @ARGV;
my $params_size = @ARGV;
my $second = $ARGV[1];
my $fifth = $ARGV[4]; |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #Falcon | Falcon |
/* Start comment block
My Life Story
*/
// set up my bank account total
bank_account_total = 1000000 // Wish this was the case
|
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #FALSE | FALSE | {comments are in curly braces} |
http://rosettacode.org/wiki/Conway%27s_Game_of_Life | Conway's Game of Life | The Game of Life is a cellular automaton devised by the British mathematician John Horton Conway in 1970. It is the best-known example of a cellular automaton.
Conway's game of life is described here:
A cell C is represented by a 1 when alive, or 0 when dead, in an m-by-m (or m×m) square array of cells.
We calculate N - the sum of live cells in C's eight-location neighbourhood, then cell C is alive or dead in the next generation based on the following table:
C N new C
1 0,1 -> 0 # Lonely
1 4,5,6,7,8 -> 0 # Overcrowded
1 2,3 -> 1 # Lives
0 3 -> 1 # It takes three to give birth!
0 0,1,2,4,5,6,7,8 -> 0 # Barren
Assume cells beyond the boundary are always dead.
The "game" is actually a zero-player game, meaning that its evolution is determined by its initial state, needing no input from human players. One interacts with the Game of Life by creating an initial configuration and observing how it evolves.
Task
Although you should test your implementation on more complex examples such as the glider in a larger universe, show the action of the blinker (three adjoining cells in a row all alive), over three generations, in a 3 by 3 grid.
References
Its creator John Conway, explains the game of life. Video from numberphile on youtube.
John Conway Inventing Game of Life - Numberphile video.
Related task
Langton's ant - another well known cellular automaton.
| #MANOOL | MANOOL |
{ {extern "manool.org.18/std/0.3/all"} in
: let { N = 40; M = 80 } in
: let { G = 99 } in
: let
{ Display =
{ proc { B } as
: for { I = Range[N]$ } do
: do Out.WriteLine[] after
: for { J = Range[M]$ } do
Out.Write[{if B[I; J] <> 0 then "*" else " "}]
}
}
in
: var { B = {array N of: array M of 0} } in
-- initialization
B[19; 41] = 1
B[20; 40] = 1
B[21; 40] = 1
B[22; 40] = 1
B[22; 41] = 1
B[22; 42] = 1
B[22; 43] = 1
B[19; 44] = 1
-- end of initialization
Out.WriteLine["Before:"]; Display[B]
{ var { NextB = B } in
: repeat G do
: do {assign B = NextB; NextB = B} after
: for { I = Range[N]$ } do
: var { Up = (I - 1).Mod[N]; Down = (I + 1).Mod[N] } in
: for { J = Range[M]$ } do
: var { Left = (J - 1).Mod[M]; Right = (J + 1).Mod[M] } in
: var
{ Count =
B[Up ; Left ] +
B[Up ; J ] +
B[Up ; Right] +
B[I ; Right] +
B[Down; Right] +
B[Down; J ] +
B[Down; Left ] +
B[I ; Left ]
}
in
NextB[I; J] =
{ if Count == 2 then B[I; J] else
: if Count == 3 then 1 else
0
}
}
Out.WriteLine["After " G " generations:"]; Display[B]
}
|
http://rosettacode.org/wiki/Conditional_structures | Conditional structures | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
List the conditional structures offered by a programming language. See Wikipedia: conditionals for descriptions.
Common conditional structures include if-then-else and switch.
Less common are arithmetic if, ternary operator and Hash-based conditionals.
Arithmetic if allows tight control over computed gotos, which optimizers have a hard time to figure out.
| #Efene | Efene |
show_if_with_parenthesis = fn (Num) {
if (Num == 1) {
io.format("is one~n")
}
else if (Num === 2) {
io.format("is two~n")
}
else {
io.format("not one not two~n")
}
}
show_if_without_parenthesis = fn (Num) {
if Num == 1 {
io.format("is one~n")
}
else if Num === 2 {
io.format("is two~n")
}
else {
io.format("not one not two~n")
}
}
show_switch_with_parenthesis = fn (Num) {
switch (Num) {
case (1) {
io.format("one!~n")
}
case (2) {
io.format("two!~n")
}
else {
io.format("else~n")
}
}
}
show_switch_without_parenthesis = fn (Num) {
switch (Num) {
case 1 {
io.format("one!~n")
}
case 2 {
io.format("two!~n")
}
else {
io.format("else~n")
}
}
}
@public
run = fn () {
show_if_with_parenthesis(random.uniform(3))
show_if_without_parenthesis(random.uniform(3))
show_switch_with_parenthesis(random.uniform(3))
show_switch_without_parenthesis(random.uniform(3))
} |
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #SenseTalk | SenseTalk | analyze ["AA","BB","CC"]
analyze ["AA","AA","AA"]
analyze ["AA","CC","BB"]
analyze ["AA","ACB","BB","CC"]
analyze ["single_element"]
to analyze aList
put "List: " & aList
put " " & (if allEqual(aList) then "IS" else "Is NOT") && "all equal"
put " " & (if isAscending(aList) then "IS" else "Is NOT") && "strictly ascending"
end analyze
to handle allEqual strings
return the number of items in the unique items of strings is less than 2
end allEqual
to handle isAscending strings
repeat with n = 2 to the number of items in strings
if item n of strings isn't more than item n-1 of strings then
return False
end if
end repeat
return True
end isAscending |
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #Sidef | Sidef | 1..arr.end -> all{ arr[0] == arr[_] } # all equal
1..arr.end -> all{ arr[_-1] < arr[_] } # strictly ascending |
http://rosettacode.org/wiki/Comma_quibbling | Comma quibbling | Comma quibbling is a task originally set by Eric Lippert in his blog.
Task
Write a function to generate a string output which is the concatenation of input words from a list/sequence where:
An input of no words produces the output string of just the two brace characters "{}".
An input of just one word, e.g. ["ABC"], produces the output string of the word inside the two braces, e.g. "{ABC}".
An input of two words, e.g. ["ABC", "DEF"], produces the output string of the two words inside the two braces with the words separated by the string " and ", e.g. "{ABC and DEF}".
An input of three or more words, e.g. ["ABC", "DEF", "G", "H"], produces the output string of all but the last word separated by ", " with the last word separated by " and " and all within braces; e.g. "{ABC, DEF, G and H}".
Test your function with the following series of inputs showing your output here on this page:
[] # (No input words).
["ABC"]
["ABC", "DEF"]
["ABC", "DEF", "G", "H"]
Note: Assume words are non-empty strings of uppercase characters for this task.
| #Nim | Nim | proc commaQuibble(s: openArray[string]): string =
result = ""
for i, c in s:
if i > 0: result.add (if i < s.high: ", " else: " and ")
result.add c
result = "{" & result & "}"
var s = @[@[], @["ABC"], @["ABC", "DEF"], @["ABC", "DEF", "G", "H"]]
for i in s:
echo commaQuibble(i) |
http://rosettacode.org/wiki/Combinations_with_repetitions | Combinations with repetitions | The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of those sets is chosen from
S
{\displaystyle S}
.
In the real world, it is about choosing sets where there is a “large” supply of each type of element and where the order of choice does not matter.
For example:
Q: How many ways can a person choose two doughnuts from a store selling three types of doughnut: iced, jam, and plain? (i.e.,
S
{\displaystyle S}
is
{
i
c
e
d
,
j
a
m
,
p
l
a
i
n
}
{\displaystyle \{\mathrm {iced} ,\mathrm {jam} ,\mathrm {plain} \}}
,
|
S
|
=
3
{\displaystyle |S|=3}
, and
k
=
2
{\displaystyle k=2}
.)
A: 6: {iced, iced}; {iced, jam}; {iced, plain}; {jam, jam}; {jam, plain}; {plain, plain}.
Note that both the order of items within a pair, and the order of the pairs given in the answer is not significant; the pairs represent multisets.
Also note that doughnut can also be spelled donut.
Task
Write a function/program/routine/.. to generate all the combinations with repetitions of
n
{\displaystyle n}
types of things taken
k
{\displaystyle k}
at a time and use it to show an answer to the doughnut example above.
For extra credit, use the function to compute and show just the number of ways of choosing three doughnuts from a choice of ten types of doughnut. Do not show the individual choices for this part.
References
k-combination with repetitions
See also
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #Sidef | Sidef | func cwr (n, l, a = []) {
n>0 ? (^l -> map {|k| __FUNC__(n-1, l.slice(k), [a..., l[k]]) }) : a
}
cwr(2, %w(iced jam plain)).each {|a|
say a.map{ .join(' ') }.join("\n")
} |
http://rosettacode.org/wiki/Compiler/lexical_analyzer | Compiler/lexical analyzer | Definition from Wikipedia:
Lexical analysis is the process of converting a sequence of characters (such as in a computer program or web page) into a sequence of tokens (strings with an identified "meaning"). A program that performs lexical analysis may be called a lexer, tokenizer, or scanner (though "scanner" is also used to refer to the first stage of a lexer).
Task[edit]
Create a lexical analyzer for the simple programming language specified below. The
program should read input from a file and/or stdin, and write output to a file and/or
stdout. If the language being used has a lexer module/library/class, it would be great
if two versions of the solution are provided: One without the lexer module, and one with.
Input Specification
The simple programming language to be analyzed is more or less a subset of C. It supports the following tokens:
Operators
Name
Common name
Character sequence
Op_multiply
multiply
*
Op_divide
divide
/
Op_mod
mod
%
Op_add
plus
+
Op_subtract
minus
-
Op_negate
unary minus
-
Op_less
less than
<
Op_lessequal
less than or equal
<=
Op_greater
greater than
>
Op_greaterequal
greater than or equal
>=
Op_equal
equal
==
Op_notequal
not equal
!=
Op_not
unary not
!
Op_assign
assignment
=
Op_and
logical and
&&
Op_or
logical or
¦¦
The - token should always be interpreted as Op_subtract by the lexer. Turning some Op_subtract into Op_negate will be the job of the syntax analyzer, which is not part of this task.
Symbols
Name
Common name
Character
LeftParen
left parenthesis
(
RightParen
right parenthesis
)
LeftBrace
left brace
{
RightBrace
right brace
}
Semicolon
semi-colon
;
Comma
comma
,
Keywords
Name
Character sequence
Keyword_if
if
Keyword_else
else
Keyword_while
while
Keyword_print
print
Keyword_putc
putc
Identifiers and literals
These differ from the the previous tokens, in that each occurrence of them has a value associated with it.
Name
Common name
Format description
Format regex
Value
Identifier
identifier
one or more letter/number/underscore characters, but not starting with a number
[_a-zA-Z][_a-zA-Z0-9]*
as is
Integer
integer literal
one or more digits
[0-9]+
as is, interpreted as a number
Integer
char literal
exactly one character (anything except newline or single quote) or one of the allowed escape sequences, enclosed by single quotes
'([^'\n]|\\n|\\\\)'
the ASCII code point number of the character, e.g. 65 for 'A' and 10 for '\n'
String
string literal
zero or more characters (anything except newline or double quote), enclosed by double quotes
"[^"\n]*"
the characters without the double quotes and with escape sequences converted
For char and string literals, the \n escape sequence is supported to represent a new-line character.
For char and string literals, to represent a backslash, use \\.
No other special sequences are supported. This means that:
Char literals cannot represent a single quote character (value 39).
String literals cannot represent strings containing double quote characters.
Zero-width tokens
Name
Location
End_of_input
when the end of the input stream is reached
White space
Zero or more whitespace characters, or comments enclosed in /* ... */, are allowed between any two tokens, with the exceptions noted below.
"Longest token matching" is used to resolve conflicts (e.g., in order to match <= as a single token rather than the two tokens < and =).
Whitespace is required between two tokens that have an alphanumeric character or underscore at the edge.
This means: keywords, identifiers, and integer literals.
e.g. ifprint is recognized as an identifier, instead of the keywords if and print.
e.g. 42fred is invalid, and neither recognized as a number nor an identifier.
Whitespace is not allowed inside of tokens (except for chars and strings where they are part of the value).
e.g. & & is invalid, and not interpreted as the && operator.
For example, the following two program fragments are equivalent, and should produce the same token stream except for the line and column positions:
if ( p /* meaning n is prime */ ) {
print ( n , " " ) ;
count = count + 1 ; /* number of primes found so far */
}
if(p){print(n," ");count=count+1;}
Complete list of token names
End_of_input Op_multiply Op_divide Op_mod Op_add Op_subtract
Op_negate Op_not Op_less Op_lessequal Op_greater Op_greaterequal
Op_equal Op_notequal Op_assign Op_and Op_or Keyword_if
Keyword_else Keyword_while Keyword_print Keyword_putc LeftParen RightParen
LeftBrace RightBrace Semicolon Comma Identifier Integer
String
Output Format
The program output should be a sequence of lines, each consisting of the following whitespace-separated fields:
the line number where the token starts
the column number where the token starts
the token name
the token value (only for Identifier, Integer, and String tokens)
the number of spaces between fields is up to you. Neatly aligned is nice, but not a requirement.
This task is intended to be used as part of a pipeline, with the other compiler tasks - for example:
lex < hello.t | parse | gen | vm
Or possibly:
lex hello.t lex.out
parse lex.out parse.out
gen parse.out gen.out
vm gen.out
This implies that the output of this task (the lexical analyzer) should be suitable as input to any of the Syntax Analyzer task programs.
Diagnostics
The following error conditions should be caught:
Error
Example
Empty character constant
''
Unknown escape sequence.
\r
Multi-character constant.
'xx'
End-of-file in comment. Closing comment characters not found.
End-of-file while scanning string literal. Closing string character not found.
End-of-line while scanning string literal. Closing string character not found before end-of-line.
Unrecognized character.
|
Invalid number. Starts like a number, but ends in non-numeric characters.
123abc
Test Cases
Input
Output
Test Case 1:
/*
Hello world
*/
print("Hello, World!\n");
4 1 Keyword_print
4 6 LeftParen
4 7 String "Hello, World!\n"
4 24 RightParen
4 25 Semicolon
5 1 End_of_input
Test Case 2:
/*
Show Ident and Integers
*/
phoenix_number = 142857;
print(phoenix_number, "\n");
4 1 Identifier phoenix_number
4 16 Op_assign
4 18 Integer 142857
4 24 Semicolon
5 1 Keyword_print
5 6 LeftParen
5 7 Identifier phoenix_number
5 21 Comma
5 23 String "\n"
5 27 RightParen
5 28 Semicolon
6 1 End_of_input
Test Case 3:
/*
All lexical tokens - not syntactically correct, but that will
have to wait until syntax analysis
*/
/* Print */ print /* Sub */ -
/* Putc */ putc /* Lss */ <
/* If */ if /* Gtr */ >
/* Else */ else /* Leq */ <=
/* While */ while /* Geq */ >=
/* Lbrace */ { /* Eq */ ==
/* Rbrace */ } /* Neq */ !=
/* Lparen */ ( /* And */ &&
/* Rparen */ ) /* Or */ ||
/* Uminus */ - /* Semi */ ;
/* Not */ ! /* Comma */ ,
/* Mul */ * /* Assign */ =
/* Div */ / /* Integer */ 42
/* Mod */ % /* String */ "String literal"
/* Add */ + /* Ident */ variable_name
/* character literal */ '\n'
/* character literal */ '\\'
/* character literal */ ' '
5 16 Keyword_print
5 40 Op_subtract
6 16 Keyword_putc
6 40 Op_less
7 16 Keyword_if
7 40 Op_greater
8 16 Keyword_else
8 40 Op_lessequal
9 16 Keyword_while
9 40 Op_greaterequal
10 16 LeftBrace
10 40 Op_equal
11 16 RightBrace
11 40 Op_notequal
12 16 LeftParen
12 40 Op_and
13 16 RightParen
13 40 Op_or
14 16 Op_subtract
14 40 Semicolon
15 16 Op_not
15 40 Comma
16 16 Op_multiply
16 40 Op_assign
17 16 Op_divide
17 40 Integer 42
18 16 Op_mod
18 40 String "String literal"
19 16 Op_add
19 40 Identifier variable_name
20 26 Integer 10
21 26 Integer 92
22 26 Integer 32
23 1 End_of_input
Test Case 4:
/*** test printing, embedded \n and comments with lots of '*' ***/
print(42);
print("\nHello World\nGood Bye\nok\n");
print("Print a slash n - \\n.\n");
2 1 Keyword_print
2 6 LeftParen
2 7 Integer 42
2 9 RightParen
2 10 Semicolon
3 1 Keyword_print
3 6 LeftParen
3 7 String "\nHello World\nGood Bye\nok\n"
3 38 RightParen
3 39 Semicolon
4 1 Keyword_print
4 6 LeftParen
4 7 String "Print a slash n - \\n.\n"
4 33 RightParen
4 34 Semicolon
5 1 End_of_input
Additional examples
Your solution should pass all the test cases above and the additional tests found Here.
Reference
The C and Python versions can be considered reference implementations.
Related Tasks
Syntax Analyzer task
Code Generator task
Virtual Machine Interpreter task
AST Interpreter task
| #Scheme | Scheme |
(import (scheme base)
(scheme char)
(scheme file)
(scheme process-context)
(scheme write))
(define *symbols* (list (cons #\( 'LeftParen)
(cons #\) 'RightParen)
(cons #\{ 'LeftBrace)
(cons #\} 'RightBrace)
(cons #\; 'Semicolon)
(cons #\, 'Comma)
(cons #\* 'Op_multiply)
(cons #\/ 'Op_divide)
(cons #\% 'Op_mod)
(cons #\+ 'Op_add)
(cons #\- 'Op_subtract)))
(define *keywords* (list (cons 'if 'Keyword_if)
(cons 'else 'Keyword_else)
(cons 'while 'Keyword_while)
(cons 'print 'Keyword_print)
(cons 'putc 'Keyword_putc)))
;; return list of tokens from current port
(define (read-tokens)
; information on position in input
(define line 1)
(define col 0)
(define next-char #f)
; get char, updating line/col posn
(define (get-next-char)
(if (char? next-char) ; check for returned character
(let ((c next-char))
(set! next-char #f)
c)
(let ((c (read-char)))
(cond ((and (not (eof-object? c))
(char=? c #\newline))
(set! col 0)
(set! line (+ 1 line))
(get-next-char))
(else
(set! col (+ 1 col))
c)))))
(define (push-char c)
(set! next-char c))
; step over any whitespace or comments
(define (skip-whitespace+comment)
(let loop ()
(let ((c (get-next-char)))
(cond ((eof-object? c)
'())
((char-whitespace? c) ; ignore whitespace
(loop))
((char=? c #\/) ; check for comments
(if (char=? (peek-char) #\*) ; found start of comment
(begin ; eat comment
(get-next-char)
(let m ((c (get-next-char)))
(cond ((eof-object? c)
(error "End of file in comment"))
((and (char=? c #\*)
(char=? (peek-char) #\/))
(get-next-char)) ; eat / and end
(else
(m (get-next-char)))))
(loop)) ; continue looking for whitespace / more comments
(push-char #\/))) ; not comment, so put / back and return
(else ; return to stream, as not a comment or space char
(push-char c))))))
; read next token from input
(define (next-token)
(define (read-string) ; returns string value along with " " marks
(let loop ((chars '(#\"))) ; " (needed to appease Rosetta code's highlighter)
(cond ((eof-object? (peek-char))
(error "End of file while scanning string literal."))
((char=? (peek-char) #\newline)
(error "End of line while scanning string literal."))
((char=? (peek-char) #\") ; "
(get-next-char) ; consume the final quote
(list->string (reverse (cons #\" chars)))) ; " highlighter)
(else
(loop (cons (get-next-char) chars))))))
(define (read-identifier initial-c) ; returns identifier as a Scheme symbol
(do ((chars (list initial-c) (cons c chars))
(c (get-next-char) (get-next-char)))
((or (eof-object? c) ; finish when hit end of file
(not (or (char-numeric? c) ; or a character not permitted in an identifier
(char-alphabetic? c)
(char=? c #\_))))
(push-char c) ; return last character to stream
(string->symbol (list->string (reverse chars))))))
(define (read-number initial-c) ; returns integer read as a Scheme integer
(let loop ((res (digit-value initial-c))
(c (get-next-char)))
(cond ((char-alphabetic? c)
(error "Invalid number - ends in alphabetic chars"))
((char-numeric? c)
(loop (+ (* res 10) (digit-value c))
(get-next-char)))
(else
(push-char c) ; return non-number to stream
res))))
; select op symbol based on if there is a following = sign
(define (check-eq-extend start-line start-col opeq op)
(if (char=? (peek-char) #\=)
(begin (get-next-char) ; consume it
(list start-line start-col opeq))
(list start-line start-col op)))
;
(let* ((start-line line) ; save start position of tokens
(start-col col)
(c (get-next-char)))
(cond ((eof-object? c)
(list start-line start-col 'End_of_input))
((char-alphabetic? c) ; read an identifier
(let ((id (read-identifier c)))
(if (assq id *keywords*) ; check if identifier is a keyword
(list start-line start-col (cdr (assq id *keywords*)))
(list start-line start-col 'Identifier id))))
((char-numeric? c) ; read a number
(list start-line start-col 'Integer (read-number c)))
(else
(case c
((#\( #\) #\{ #\} #\; #\, #\* #\/ #\% #\+ #\-)
(list start-line start-col (cdr (assq c *symbols*))))
((#\<)
(check-eq-extend start-line start-col 'Op_lessequal 'Op_less))
((#\>)
(check-eq-extend start-line start-col 'Op_greaterequal 'Op_greater))
((#\=)
(check-eq-extend start-line start-col 'Op_equal 'Op_assign))
((#\!)
(check-eq-extend start-line start-col 'Op_notequal 'Op_not))
((#\& #\|)
(if (char=? (peek-char) c) ; looks for && or ||
(begin (get-next-char) ; consume second character if valid
(list start-line start-col
(if (char=? c #\&) 'Op_and 'Op_or)))
(push-char c)))
((#\") ; "
(list start-line start-col 'String (read-string)))
((#\')
(let* ((c1 (get-next-char))
(c2 (get-next-char)))
(cond ((or (eof-object? c1)
(eof-object? c2))
(error "Incomplete character constant"))
((char=? c1 #\')
(error "Empty character constant"))
((and (char=? c2 #\') ; case of single character
(not (char=? c1 #\\)))
(list start-line start-col 'Integer (char->integer c1)))
((and (char=? c1 #\\) ; case of escaped character
(char=? (peek-char) #\'))
(get-next-char) ; consume the ending '
(cond ((char=? c2 #\n)
(list start-line start-col 'Integer 10))
((char=? c2 #\\)
(list start-line start-col 'Integer (char->integer c2)))
(else
(error "Unknown escape sequence"))))
(else
(error "Multi-character constant")))))
(else
(error "Unrecognised character")))))))
;
(let loop ((tokens '())) ; loop, ignoring space/comments, while reading tokens
(skip-whitespace+comment)
(let ((tok (next-token)))
(if (eof-object? (peek-char)) ; check if at end of input
(reverse (cons tok tokens))
(loop (cons tok tokens))))))
(define (lexer filename)
(with-input-from-file filename
(lambda () (read-tokens))))
;; output tokens to stdout, tab separated
;; line number, column number, token type, optional value
(define (display-tokens tokens)
(for-each
(lambda (token)
(display (list-ref token 0))
(display #\tab) (display (list-ref token 1))
(display #\tab) (display (list-ref token 2))
(when (= 4 (length token))
(display #\tab) (display (list-ref token 3)))
(newline))
tokens))
;; read from filename passed on command line
(if (= 2 (length (command-line)))
(display-tokens (lexer (cadr (command-line))))
(display "Error: provide program filename\n"))
|
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Phix | Phix | with javascript_semantics
constant cmd = command_line()
?cmd
if cmd[1]=cmd[2] then
printf(1,"Compiled executable name: %s\n",{cmd[1]})
else
printf(1,"Interpreted (using %s) source name: %s\n",cmd[1..2])
end if
if length(cmd)>2 then
puts(1,"Command line arguments:\n")
for i = 3 to length(cmd) do
printf(1,"#%d : %s\n",{i,cmd[i]})
end for
end if
|
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #PHP | PHP | <?php
$program_name = $argv[0];
$second_arg = $argv[2];
$all_args_without_program_name = array_shift($argv);
|
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #Fancy | Fancy | # Comments starts with "#"
# and last until the end of the line
|
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #Fermat | Fermat | Function Foo(n) =
{Comments within a function are enclosed within curly brackets.}
{You can make multi-line comments
such as this one.}
n:=n^2 + 3n - 222; {Comments can go after a semicolon.}
n:=n+1;
n.
; comments between functions are preceded by semicolons, like this
Function Bar(n) =
2n-1. |
http://rosettacode.org/wiki/Conway%27s_Game_of_Life | Conway's Game of Life | The Game of Life is a cellular automaton devised by the British mathematician John Horton Conway in 1970. It is the best-known example of a cellular automaton.
Conway's game of life is described here:
A cell C is represented by a 1 when alive, or 0 when dead, in an m-by-m (or m×m) square array of cells.
We calculate N - the sum of live cells in C's eight-location neighbourhood, then cell C is alive or dead in the next generation based on the following table:
C N new C
1 0,1 -> 0 # Lonely
1 4,5,6,7,8 -> 0 # Overcrowded
1 2,3 -> 1 # Lives
0 3 -> 1 # It takes three to give birth!
0 0,1,2,4,5,6,7,8 -> 0 # Barren
Assume cells beyond the boundary are always dead.
The "game" is actually a zero-player game, meaning that its evolution is determined by its initial state, needing no input from human players. One interacts with the Game of Life by creating an initial configuration and observing how it evolves.
Task
Although you should test your implementation on more complex examples such as the glider in a larger universe, show the action of the blinker (three adjoining cells in a row all alive), over three generations, in a 3 by 3 grid.
References
Its creator John Conway, explains the game of life. Video from numberphile on youtube.
John Conway Inventing Game of Life - Numberphile video.
Related task
Langton's ant - another well known cellular automaton.
| #Mathematica_.2F_Wolfram_Language | Mathematica / Wolfram Language | CellularAutomaton[{224,{2,{{2,2,2},{2,1,2},{2,2,2}}},{1,1}}, startconfiguration, steps]; |
http://rosettacode.org/wiki/Conditional_structures | Conditional structures | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
List the conditional structures offered by a programming language. See Wikipedia: conditionals for descriptions.
Common conditional structures include if-then-else and switch.
Less common are arithmetic if, ternary operator and Hash-based conditionals.
Arithmetic if allows tight control over computed gotos, which optimizers have a hard time to figure out.
| #Ela | Ela | if x < 0 then 0 else x |
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #Tailspin | Tailspin |
// matcher testing if the array contains anything not equal to the first element
templates allEqual
when <[](..1)> do 1 !
when <[<~=$(1)>]> do 0 !
otherwise 1 !
end allEqual
templates strictAscending
def a: $;
1 -> #
when <$a::length..> do 1 !
when <?($a($) <..~$a($+1)>)> do $ + 1 -> #
otherwise 0 !
end strictAscending
// Of course we could just use the same kind of loop for equality
templates strictEqual
def a: $;
1 -> #
when <$a::length..> do 1 !
when <?($a($) <=$a($+1)>)> do $ + 1 -> #
otherwise 0 !
end strictEqual
|
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #Tcl | Tcl | tcl::mathop::eq {*}$strings; # All values string-equal
tcl::mathop::< {*}$strings; # All values in strict order |
http://rosettacode.org/wiki/Comma_quibbling | Comma quibbling | Comma quibbling is a task originally set by Eric Lippert in his blog.
Task
Write a function to generate a string output which is the concatenation of input words from a list/sequence where:
An input of no words produces the output string of just the two brace characters "{}".
An input of just one word, e.g. ["ABC"], produces the output string of the word inside the two braces, e.g. "{ABC}".
An input of two words, e.g. ["ABC", "DEF"], produces the output string of the two words inside the two braces with the words separated by the string " and ", e.g. "{ABC and DEF}".
An input of three or more words, e.g. ["ABC", "DEF", "G", "H"], produces the output string of all but the last word separated by ", " with the last word separated by " and " and all within braces; e.g. "{ABC, DEF, G and H}".
Test your function with the following series of inputs showing your output here on this page:
[] # (No input words).
["ABC"]
["ABC", "DEF"]
["ABC", "DEF", "G", "H"]
Note: Assume words are non-empty strings of uppercase characters for this task.
| #Oberon-2 | Oberon-2 |
MODULE CommaQuibbling;
IMPORT
NPCT:Args,
Strings,
Out;
VAR
str: ARRAY 256 OF CHAR;
PROCEDURE Do(VAR s: ARRAY OF CHAR);
VAR
aux: ARRAY 128 OF CHAR;
i,params: LONGINT;
BEGIN
params := Args.Number() - 1;
CASE params OF
0:
COPY("{}",s)
|1:
Args.At(1,aux);
Strings.Append("{",s);
Strings.Append(aux,s);
Strings.Append("}",s);
ELSE
Strings.Append("{",s);
FOR i := 1 TO params - 1 DO
Args.At(i,aux);
Strings.Append(aux,s);
IF i # params - 1 THEN
Strings.Append(", ",s)
ELSE
Strings.Append(" and ", s)
END
END;
Args.At(params,aux);
Strings.Append(aux,s);
Strings.Append("}",s)
END;
END Do;
BEGIN
Do(str);
Out.String(":> ");Out.String(str);Out.Ln
END CommaQuibbling.
|
http://rosettacode.org/wiki/Combinations_with_repetitions | Combinations with repetitions | The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of those sets is chosen from
S
{\displaystyle S}
.
In the real world, it is about choosing sets where there is a “large” supply of each type of element and where the order of choice does not matter.
For example:
Q: How many ways can a person choose two doughnuts from a store selling three types of doughnut: iced, jam, and plain? (i.e.,
S
{\displaystyle S}
is
{
i
c
e
d
,
j
a
m
,
p
l
a
i
n
}
{\displaystyle \{\mathrm {iced} ,\mathrm {jam} ,\mathrm {plain} \}}
,
|
S
|
=
3
{\displaystyle |S|=3}
, and
k
=
2
{\displaystyle k=2}
.)
A: 6: {iced, iced}; {iced, jam}; {iced, plain}; {jam, jam}; {jam, plain}; {plain, plain}.
Note that both the order of items within a pair, and the order of the pairs given in the answer is not significant; the pairs represent multisets.
Also note that doughnut can also be spelled donut.
Task
Write a function/program/routine/.. to generate all the combinations with repetitions of
n
{\displaystyle n}
types of things taken
k
{\displaystyle k}
at a time and use it to show an answer to the doughnut example above.
For extra credit, use the function to compute and show just the number of ways of choosing three doughnuts from a choice of ten types of doughnut. Do not show the individual choices for this part.
References
k-combination with repetitions
See also
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #Standard_ML | Standard ML | let rec combs_with_rep k xxs =
match k, xxs with
| 0, _ -> [[]]
| _, [] -> []
| k, x::xs ->
List.map (fun ys -> x::ys) (combs_with_rep (k-1) xxs)
@ combs_with_rep k xs |
http://rosettacode.org/wiki/Combinations_with_repetitions | Combinations with repetitions | The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of those sets is chosen from
S
{\displaystyle S}
.
In the real world, it is about choosing sets where there is a “large” supply of each type of element and where the order of choice does not matter.
For example:
Q: How many ways can a person choose two doughnuts from a store selling three types of doughnut: iced, jam, and plain? (i.e.,
S
{\displaystyle S}
is
{
i
c
e
d
,
j
a
m
,
p
l
a
i
n
}
{\displaystyle \{\mathrm {iced} ,\mathrm {jam} ,\mathrm {plain} \}}
,
|
S
|
=
3
{\displaystyle |S|=3}
, and
k
=
2
{\displaystyle k=2}
.)
A: 6: {iced, iced}; {iced, jam}; {iced, plain}; {jam, jam}; {jam, plain}; {plain, plain}.
Note that both the order of items within a pair, and the order of the pairs given in the answer is not significant; the pairs represent multisets.
Also note that doughnut can also be spelled donut.
Task
Write a function/program/routine/.. to generate all the combinations with repetitions of
n
{\displaystyle n}
types of things taken
k
{\displaystyle k}
at a time and use it to show an answer to the doughnut example above.
For extra credit, use the function to compute and show just the number of ways of choosing three doughnuts from a choice of ten types of doughnut. Do not show the individual choices for this part.
References
k-combination with repetitions
See also
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #Stata | Stata | function combrep(v,k) {
n = cols(v)
a = J(comb(n+k-1,k),k,v[1])
u = J(1,k,1)
for (i=2; 1; i++) {
for (j=k; j>0; j--) {
if (u[j]<n) break
}
if (j<1) return(a)
m = u[j]+1
for (; j<=k; j++) u[j] = m
a[i,.] = v[u]
}
}
combrep(("iced","jam","plain"),2)
a = combrep(1..10,3)
rows(a) |
http://rosettacode.org/wiki/Compiler/lexical_analyzer | Compiler/lexical analyzer | Definition from Wikipedia:
Lexical analysis is the process of converting a sequence of characters (such as in a computer program or web page) into a sequence of tokens (strings with an identified "meaning"). A program that performs lexical analysis may be called a lexer, tokenizer, or scanner (though "scanner" is also used to refer to the first stage of a lexer).
Task[edit]
Create a lexical analyzer for the simple programming language specified below. The
program should read input from a file and/or stdin, and write output to a file and/or
stdout. If the language being used has a lexer module/library/class, it would be great
if two versions of the solution are provided: One without the lexer module, and one with.
Input Specification
The simple programming language to be analyzed is more or less a subset of C. It supports the following tokens:
Operators
Name
Common name
Character sequence
Op_multiply
multiply
*
Op_divide
divide
/
Op_mod
mod
%
Op_add
plus
+
Op_subtract
minus
-
Op_negate
unary minus
-
Op_less
less than
<
Op_lessequal
less than or equal
<=
Op_greater
greater than
>
Op_greaterequal
greater than or equal
>=
Op_equal
equal
==
Op_notequal
not equal
!=
Op_not
unary not
!
Op_assign
assignment
=
Op_and
logical and
&&
Op_or
logical or
¦¦
The - token should always be interpreted as Op_subtract by the lexer. Turning some Op_subtract into Op_negate will be the job of the syntax analyzer, which is not part of this task.
Symbols
Name
Common name
Character
LeftParen
left parenthesis
(
RightParen
right parenthesis
)
LeftBrace
left brace
{
RightBrace
right brace
}
Semicolon
semi-colon
;
Comma
comma
,
Keywords
Name
Character sequence
Keyword_if
if
Keyword_else
else
Keyword_while
while
Keyword_print
print
Keyword_putc
putc
Identifiers and literals
These differ from the the previous tokens, in that each occurrence of them has a value associated with it.
Name
Common name
Format description
Format regex
Value
Identifier
identifier
one or more letter/number/underscore characters, but not starting with a number
[_a-zA-Z][_a-zA-Z0-9]*
as is
Integer
integer literal
one or more digits
[0-9]+
as is, interpreted as a number
Integer
char literal
exactly one character (anything except newline or single quote) or one of the allowed escape sequences, enclosed by single quotes
'([^'\n]|\\n|\\\\)'
the ASCII code point number of the character, e.g. 65 for 'A' and 10 for '\n'
String
string literal
zero or more characters (anything except newline or double quote), enclosed by double quotes
"[^"\n]*"
the characters without the double quotes and with escape sequences converted
For char and string literals, the \n escape sequence is supported to represent a new-line character.
For char and string literals, to represent a backslash, use \\.
No other special sequences are supported. This means that:
Char literals cannot represent a single quote character (value 39).
String literals cannot represent strings containing double quote characters.
Zero-width tokens
Name
Location
End_of_input
when the end of the input stream is reached
White space
Zero or more whitespace characters, or comments enclosed in /* ... */, are allowed between any two tokens, with the exceptions noted below.
"Longest token matching" is used to resolve conflicts (e.g., in order to match <= as a single token rather than the two tokens < and =).
Whitespace is required between two tokens that have an alphanumeric character or underscore at the edge.
This means: keywords, identifiers, and integer literals.
e.g. ifprint is recognized as an identifier, instead of the keywords if and print.
e.g. 42fred is invalid, and neither recognized as a number nor an identifier.
Whitespace is not allowed inside of tokens (except for chars and strings where they are part of the value).
e.g. & & is invalid, and not interpreted as the && operator.
For example, the following two program fragments are equivalent, and should produce the same token stream except for the line and column positions:
if ( p /* meaning n is prime */ ) {
print ( n , " " ) ;
count = count + 1 ; /* number of primes found so far */
}
if(p){print(n," ");count=count+1;}
Complete list of token names
End_of_input Op_multiply Op_divide Op_mod Op_add Op_subtract
Op_negate Op_not Op_less Op_lessequal Op_greater Op_greaterequal
Op_equal Op_notequal Op_assign Op_and Op_or Keyword_if
Keyword_else Keyword_while Keyword_print Keyword_putc LeftParen RightParen
LeftBrace RightBrace Semicolon Comma Identifier Integer
String
Output Format
The program output should be a sequence of lines, each consisting of the following whitespace-separated fields:
the line number where the token starts
the column number where the token starts
the token name
the token value (only for Identifier, Integer, and String tokens)
the number of spaces between fields is up to you. Neatly aligned is nice, but not a requirement.
This task is intended to be used as part of a pipeline, with the other compiler tasks - for example:
lex < hello.t | parse | gen | vm
Or possibly:
lex hello.t lex.out
parse lex.out parse.out
gen parse.out gen.out
vm gen.out
This implies that the output of this task (the lexical analyzer) should be suitable as input to any of the Syntax Analyzer task programs.
Diagnostics
The following error conditions should be caught:
Error
Example
Empty character constant
''
Unknown escape sequence.
\r
Multi-character constant.
'xx'
End-of-file in comment. Closing comment characters not found.
End-of-file while scanning string literal. Closing string character not found.
End-of-line while scanning string literal. Closing string character not found before end-of-line.
Unrecognized character.
|
Invalid number. Starts like a number, but ends in non-numeric characters.
123abc
Test Cases
Input
Output
Test Case 1:
/*
Hello world
*/
print("Hello, World!\n");
4 1 Keyword_print
4 6 LeftParen
4 7 String "Hello, World!\n"
4 24 RightParen
4 25 Semicolon
5 1 End_of_input
Test Case 2:
/*
Show Ident and Integers
*/
phoenix_number = 142857;
print(phoenix_number, "\n");
4 1 Identifier phoenix_number
4 16 Op_assign
4 18 Integer 142857
4 24 Semicolon
5 1 Keyword_print
5 6 LeftParen
5 7 Identifier phoenix_number
5 21 Comma
5 23 String "\n"
5 27 RightParen
5 28 Semicolon
6 1 End_of_input
Test Case 3:
/*
All lexical tokens - not syntactically correct, but that will
have to wait until syntax analysis
*/
/* Print */ print /* Sub */ -
/* Putc */ putc /* Lss */ <
/* If */ if /* Gtr */ >
/* Else */ else /* Leq */ <=
/* While */ while /* Geq */ >=
/* Lbrace */ { /* Eq */ ==
/* Rbrace */ } /* Neq */ !=
/* Lparen */ ( /* And */ &&
/* Rparen */ ) /* Or */ ||
/* Uminus */ - /* Semi */ ;
/* Not */ ! /* Comma */ ,
/* Mul */ * /* Assign */ =
/* Div */ / /* Integer */ 42
/* Mod */ % /* String */ "String literal"
/* Add */ + /* Ident */ variable_name
/* character literal */ '\n'
/* character literal */ '\\'
/* character literal */ ' '
5 16 Keyword_print
5 40 Op_subtract
6 16 Keyword_putc
6 40 Op_less
7 16 Keyword_if
7 40 Op_greater
8 16 Keyword_else
8 40 Op_lessequal
9 16 Keyword_while
9 40 Op_greaterequal
10 16 LeftBrace
10 40 Op_equal
11 16 RightBrace
11 40 Op_notequal
12 16 LeftParen
12 40 Op_and
13 16 RightParen
13 40 Op_or
14 16 Op_subtract
14 40 Semicolon
15 16 Op_not
15 40 Comma
16 16 Op_multiply
16 40 Op_assign
17 16 Op_divide
17 40 Integer 42
18 16 Op_mod
18 40 String "String literal"
19 16 Op_add
19 40 Identifier variable_name
20 26 Integer 10
21 26 Integer 92
22 26 Integer 32
23 1 End_of_input
Test Case 4:
/*** test printing, embedded \n and comments with lots of '*' ***/
print(42);
print("\nHello World\nGood Bye\nok\n");
print("Print a slash n - \\n.\n");
2 1 Keyword_print
2 6 LeftParen
2 7 Integer 42
2 9 RightParen
2 10 Semicolon
3 1 Keyword_print
3 6 LeftParen
3 7 String "\nHello World\nGood Bye\nok\n"
3 38 RightParen
3 39 Semicolon
4 1 Keyword_print
4 6 LeftParen
4 7 String "Print a slash n - \\n.\n"
4 33 RightParen
4 34 Semicolon
5 1 End_of_input
Additional examples
Your solution should pass all the test cases above and the additional tests found Here.
Reference
The C and Python versions can be considered reference implementations.
Related Tasks
Syntax Analyzer task
Code Generator task
Virtual Machine Interpreter task
AST Interpreter task
| #Standard_ML | Standard ML | (*------------------------------------------------------------------*)
(* The Rosetta Code lexical analyzer, in Standard ML. Based on the ATS
and the OCaml. The intended compiler is Mlton or Poly/ML; there is
a tiny difference near the end of the file, depending on which
compiler is used. *)
(*------------------------------------------------------------------*)
(* The following functions are compatible with ASCII. *)
fun
is_digit ichar =
48 <= ichar andalso ichar <= 57
fun
is_lower ichar =
97 <= ichar andalso ichar <= 122
fun
is_upper ichar =
65 <= ichar andalso ichar <= 90
fun
is_alpha ichar =
is_lower ichar orelse is_upper ichar
fun
is_alnum ichar =
is_digit ichar orelse is_alpha ichar
fun
is_ident_start ichar =
is_alpha ichar orelse ichar = 95
fun
is_ident_continuation ichar =
is_alnum ichar orelse ichar = 95
fun
is_space ichar =
ichar = 32 orelse (9 <= ichar andalso ichar <= 13)
(*------------------------------------------------------------------*)
(* Character input more like that of C. There are various advantages
and disadvantages to this method, but key points in its favor are:
(a) it is how character input is done in the original ATS code, (b)
Unicode code points are 21-bit positive integers. *)
val eof = ~1
fun
input_ichar inpf =
case TextIO.input1 inpf of
NONE => eof
| SOME c => Char.ord c
(*------------------------------------------------------------------*)
(* The type of an input character. *)
structure Ch =
struct
type t = {
ichar : int,
line_no : int,
column_no : int
}
end
(*------------------------------------------------------------------*)
(* Inputting with unlimited pushback, and with counting of lines and
columns. *)
structure Inp =
struct
type t = {
inpf : TextIO.instream,
pushback : Ch.t list,
line_no : int,
column_no : int
}
fun
of_instream inpf =
{
inpf = inpf,
pushback = [],
line_no = 1,
column_no = 1
} : t
fun
get_ch ({ inpf = inpf,
pushback = pushback,
line_no = line_no,
column_no = column_no } : t) =
case pushback of
ch :: tail =>
let
val inp = { inpf = inpf,
pushback = tail,
line_no = line_no,
column_no = column_no }
in
(ch, inp)
end
| [] =>
let
val ichar = input_ichar inpf
val ch = { ichar = ichar,
line_no = line_no,
column_no = column_no }
in
if ichar = Char.ord #"\n" then
let
val inp = { inpf = inpf,
pushback = [],
line_no = line_no + 1,
column_no = 1 }
in
(ch, inp)
end
else
let
val inp = { inpf = inpf,
pushback = [],
line_no = line_no,
column_no = column_no + 1 }
in
(ch, inp)
end
end
fun
push_back_ch (ch, inp : t) =
{
inpf = #inpf inp,
pushback = ch :: #pushback inp,
line_no = #line_no inp,
column_no = #column_no inp
}
end
(*------------------------------------------------------------------*)
(* Tokens, appearing in tuples with arguments, and with line and
column numbers. The tokens are integers, so they can be used as
array indices. *)
val token_ELSE = 0
val token_IF = 1
val token_PRINT = 2
val token_PUTC = 3
val token_WHILE = 4
val token_MULTIPLY = 5
val token_DIVIDE = 6
val token_MOD = 7
val token_ADD = 8
val token_SUBTRACT = 9
val token_NEGATE = 10
val token_LESS = 11
val token_LESSEQUAL = 12
val token_GREATER = 13
val token_GREATEREQUAL = 14
val token_EQUAL = 15
val token_NOTEQUAL = 16
val token_NOT = 17
val token_ASSIGN = 18
val token_AND = 19
val token_OR = 20
val token_LEFTPAREN = 21
val token_RIGHTPAREN = 22
val token_LEFTBRACE = 23
val token_RIGHTBRACE = 24
val token_SEMICOLON = 25
val token_COMMA = 26
val token_IDENTIFIER = 27
val token_INTEGER = 28
val token_STRING = 29
val token_END_OF_INPUT = 30
(* A *very* simple perfect hash for the reserved words. (Yes, this is
overkill, except for demonstration of the principle.) *)
val reserved_words =
Vector.fromList ["if", "print", "else",
"", "putc", "",
"", "while", ""]
val reserved_word_tokens =
Vector.fromList [token_IF, token_PRINT, token_ELSE,
token_IDENTIFIER, token_PUTC, token_IDENTIFIER,
token_IDENTIFIER, token_WHILE, token_IDENTIFIER]
fun
reserved_word_lookup (s, line_no, column_no) =
if (String.size s) < 2 then
(token_IDENTIFIER, s, line_no, column_no)
else
let
val hashval =
(Char.ord (String.sub (s, 0)) +
Char.ord (String.sub (s, 1)))
mod 9
val token = Vector.sub (reserved_word_tokens, hashval)
in
if token = token_IDENTIFIER orelse
s <> Vector.sub (reserved_words, hashval) then
(token_IDENTIFIER, s, line_no, column_no)
else
(token, s, line_no, column_no)
end
(* Token to string lookup. *)
val token_names =
Vector.fromList
["Keyword_else",
"Keyword_if",
"Keyword_print",
"Keyword_putc",
"Keyword_while",
"Op_multiply",
"Op_divide",
"Op_mod",
"Op_add",
"Op_subtract",
"Op_negate",
"Op_less",
"Op_lessequal",
"Op_greater",
"Op_greaterequal",
"Op_equal",
"Op_notequal",
"Op_not",
"Op_assign",
"Op_and",
"Op_or",
"LeftParen",
"RightParen",
"LeftBrace",
"RightBrace",
"Semicolon",
"Comma",
"Identifier",
"Integer",
"String",
"End_of_input"]
fun
token_name token =
Vector.sub (token_names, token)
(*------------------------------------------------------------------*)
exception Unterminated_comment of int * int
exception Unterminated_character_literal of int * int
exception Multicharacter_literal of int * int
exception End_of_input_in_string_literal of int * int
exception End_of_line_in_string_literal of int * int
exception Unsupported_escape of int * int * char
exception Invalid_integer_literal of int * int * string
exception Unexpected_character of int * int * char
(*------------------------------------------------------------------*)
(* Skipping past spaces and comments. (In the Rosetta Code tiny
language, a comment, if you think about it, is a kind of space.) *)
fun
scan_comment (inp, line_no, column_no) =
let
fun
loop inp =
let
val (ch, inp) = Inp.get_ch inp
in
if #ichar ch = eof then
raise Unterminated_comment (line_no, column_no)
else if #ichar ch = Char.ord #"*" then
let
val (ch1, inp) = Inp.get_ch inp
in
if #ichar ch1 = eof then
raise Unterminated_comment (line_no, column_no)
else if #ichar ch1 = Char.ord #"/" then
inp
else
loop inp
end
else
loop inp
end
in
loop inp
end
fun
skip_spaces_and_comments inp =
let
fun
loop inp =
let
val (ch, inp) = Inp.get_ch inp
in
if is_space (#ichar ch) then
loop inp
else if #ichar ch = Char.ord #"/" then
let
val (ch1, inp) = Inp.get_ch inp
in
if #ichar ch1 = Char.ord #"*" then
loop (scan_comment (inp, #line_no ch, #column_no ch))
else
let
val inp = Inp.push_back_ch (ch1, inp)
val inp = Inp.push_back_ch (ch, inp)
in
inp
end
end
else
Inp.push_back_ch (ch, inp)
end
in
loop inp
end
(*------------------------------------------------------------------*)
(* Integer literals, identifiers, and reserved words. *)
fun
scan_word (lst, inp) =
let
val (ch, inp) = Inp.get_ch inp
in
if is_ident_continuation (#ichar ch) then
scan_word (Char.chr (#ichar ch) :: lst, inp)
else
(lst, Inp.push_back_ch (ch, inp))
end
fun
scan_integer_literal inp =
let
val (ch, inp) = Inp.get_ch inp
val (lst, inp) = scan_word ([Char.chr (#ichar ch)], inp)
val s = String.implode (List.rev lst)
in
if List.all (fn c => is_digit (Char.ord c)) lst then
((token_INTEGER, s, #line_no ch, #column_no ch), inp)
else
raise Invalid_integer_literal (#line_no ch, #column_no ch, s)
end
fun
scan_identifier_or_reserved_word inp =
let
val (ch, inp) = Inp.get_ch inp
val (lst, inp) = scan_word ([Char.chr (#ichar ch)], inp)
val s = String.implode (List.rev lst)
val toktup = reserved_word_lookup (s, #line_no ch, #column_no ch)
in
(toktup, inp)
end
(*------------------------------------------------------------------*)
(* String literals. *)
fun
scan_string_literal inp =
let
val (ch, inp) = Inp.get_ch inp
fun
scan (lst, inp) =
let
val (ch1, inp) = Inp.get_ch inp
in
if #ichar ch1 = eof then
raise End_of_input_in_string_literal
(#line_no ch, #column_no ch)
else if #ichar ch1 = Char.ord #"\n" then
raise End_of_line_in_string_literal
(#line_no ch, #column_no ch)
else if #ichar ch1 = Char.ord #"\"" then
(lst, inp)
else if #ichar ch1 <> Char.ord #"\\" then
scan (Char.chr (#ichar ch1) :: lst, inp)
else
let
val (ch2, inp) = Inp.get_ch inp
in
if #ichar ch2 = Char.ord #"n" then
scan (#"n" :: #"\\" :: lst, inp)
else if #ichar ch2 = Char.ord #"\\" then
scan (#"\\" :: #"\\" :: lst, inp)
else if #ichar ch2 = eof then
raise End_of_input_in_string_literal
(#line_no ch, #column_no ch)
else if #ichar ch2 = Char.ord #"\n" then
raise End_of_line_in_string_literal
(#line_no ch, #column_no ch)
else
raise Unsupported_escape (#line_no ch1, #column_no ch1,
Char.chr (#ichar ch2))
end
end
val lst = #"\"" :: []
val (lst, inp) = scan (lst, inp)
val lst = #"\"" :: lst
val s = String.implode (List.rev lst)
in
((token_STRING, s, #line_no ch, #column_no ch), inp)
end
(*------------------------------------------------------------------*)
(* Character literals. *)
fun
scan_character_literal_without_checking_end inp =
let
val (ch, inp) = Inp.get_ch inp
val (ch1, inp) = Inp.get_ch inp
in
if #ichar ch1 = eof then
raise Unterminated_character_literal
(#line_no ch, #column_no ch)
else if #ichar ch1 = Char.ord #"\\" then
let
val (ch2, inp) = Inp.get_ch inp
in
if #ichar ch2 = eof then
raise Unterminated_character_literal
(#line_no ch, #column_no ch)
else if #ichar ch2 = Char.ord #"n" then
let
val s = Int.toString (Char.ord #"\n")
in
((token_INTEGER, s, #line_no ch, #column_no ch), inp)
end
else if #ichar ch2 = Char.ord #"\\" then
let
val s = Int.toString (Char.ord #"\\")
in
((token_INTEGER, s, #line_no ch, #column_no ch), inp)
end
else
raise Unsupported_escape (#line_no ch1, #column_no ch1,
Char.chr (#ichar ch2))
end
else
let
val s = Int.toString (#ichar ch1)
in
((token_INTEGER, s, #line_no ch, #column_no ch), inp)
end
end
fun
scan_character_literal inp =
let
val (toktup, inp) =
scan_character_literal_without_checking_end inp
val (_, _, line_no, column_no) = toktup
fun
check_end inp =
let
val (ch, inp) = Inp.get_ch inp
in
if #ichar ch = Char.ord #"'" then
inp
else
let
fun
loop_to_end (ch1 : Ch.t, inp) =
if #ichar ch1 = eof then
raise Unterminated_character_literal (line_no, column_no)
else if #ichar ch1 = Char.ord #"'" then
raise Multicharacter_literal (line_no, column_no)
else
let
val (ch1, inp) = Inp.get_ch inp
in
loop_to_end (ch1, inp)
end
in
loop_to_end (ch, inp)
end
end
val inp = check_end inp
in
(toktup, inp)
end
(*------------------------------------------------------------------*)
fun
get_next_token inp =
let
val inp = skip_spaces_and_comments inp
val (ch, inp) = Inp.get_ch inp
val ln = #line_no ch
val cn = #column_no ch
in
if #ichar ch = eof then
((token_END_OF_INPUT, "", ln, cn), inp)
else
case Char.chr (#ichar ch) of
#"," => ((token_COMMA, ",", ln, cn), inp)
| #";" => ((token_SEMICOLON, ";", ln, cn), inp)
| #"(" => ((token_LEFTPAREN, "(", ln, cn), inp)
| #")" => ((token_RIGHTPAREN, ")", ln, cn), inp)
| #"{" => ((token_LEFTBRACE, "{", ln, cn), inp)
| #"}" => ((token_RIGHTBRACE, "}", ln, cn), inp)
| #"*" => ((token_MULTIPLY, "*", ln, cn), inp)
| #"/" => ((token_DIVIDE, "/", ln, cn), inp)
| #"%" => ((token_MOD, "%", ln, cn), inp)
| #"+" => ((token_ADD, "+", ln, cn), inp)
| #"-" => ((token_SUBTRACT, "-", ln, cn), inp)
| #"<" =>
let
val (ch1, inp) = Inp.get_ch inp
in
if #ichar ch1 = Char.ord #"=" then
((token_LESSEQUAL, "<=", ln, cn), inp)
else
let
val inp = Inp.push_back_ch (ch1, inp)
in
((token_LESS, "<", ln, cn), inp)
end
end
| #">" =>
let
val (ch1, inp) = Inp.get_ch inp
in
if #ichar ch1 = Char.ord #"=" then
((token_GREATEREQUAL, ">=", ln, cn), inp)
else
let
val inp = Inp.push_back_ch (ch1, inp)
in
((token_GREATER, ">", ln, cn), inp)
end
end
| #"=" =>
let
val (ch1, inp) = Inp.get_ch inp
in
if #ichar ch1 = Char.ord #"=" then
((token_EQUAL, "==", ln, cn), inp)
else
let
val inp = Inp.push_back_ch (ch1, inp)
in
((token_ASSIGN, "=", ln, cn), inp)
end
end
| #"!" =>
let
val (ch1, inp) = Inp.get_ch inp
in
if #ichar ch1 = Char.ord #"=" then
((token_NOTEQUAL, "!=", ln, cn), inp)
else
let
val inp = Inp.push_back_ch (ch1, inp)
in
((token_NOT, "!", ln, cn), inp)
end
end
| #"&" =>
let
val (ch1, inp) = Inp.get_ch inp
in
if #ichar ch1 = Char.ord #"&" then
((token_AND, "&&", ln, cn), inp)
else
raise Unexpected_character (#line_no ch, #column_no ch,
Char.chr (#ichar ch))
end
| #"|" =>
let
val (ch1, inp) = Inp.get_ch inp
in
if #ichar ch1 = Char.ord #"|" then
((token_OR, "||", ln, cn), inp)
else
raise Unexpected_character (#line_no ch, #column_no ch,
Char.chr (#ichar ch))
end
| #"\"" =>
let
val inp = Inp.push_back_ch (ch, inp)
in
scan_string_literal inp
end
| #"'" =>
let
val inp = Inp.push_back_ch (ch, inp)
in
scan_character_literal inp
end
| _ =>
if is_digit (#ichar ch) then
let
val inp = Inp.push_back_ch (ch, inp)
in
scan_integer_literal inp
end
else if is_ident_start (#ichar ch) then
let
val inp = Inp.push_back_ch (ch, inp)
in
scan_identifier_or_reserved_word inp
end
else
raise Unexpected_character (#line_no ch, #column_no ch,
Char.chr (#ichar ch))
end
fun
output_integer_rightjust (outf, num) =
(if num < 10 then
TextIO.output (outf, " ")
else if num < 100 then
TextIO.output (outf, " ")
else if num < 1000 then
TextIO.output (outf, " ")
else if num < 10000 then
TextIO.output (outf, " ")
else
();
TextIO.output (outf, Int.toString num))
fun
print_token (outf, toktup) =
let
val (token, arg, line_no, column_no) = toktup
val name = token_name token
val (padding, str) =
if token = token_IDENTIFIER then
(" ", arg)
else if token = token_INTEGER then
(" ", arg)
else if token = token_STRING then
(" ", arg)
else("", "")
in
output_integer_rightjust (outf, line_no);
TextIO.output (outf, " ");
output_integer_rightjust (outf, column_no);
TextIO.output (outf, " ");
TextIO.output (outf, name);
TextIO.output (outf, padding);
TextIO.output (outf, str);
TextIO.output (outf, "\n")
end
fun
scan_text (outf, inp) =
let
fun
loop inp =
let
val (toktup, inp) = get_next_token inp
in
(print_token (outf, toktup);
let
val (token, _, _, _) = toktup
in
if token <> token_END_OF_INPUT then
loop inp
else
()
end)
end
in
loop inp
end
(*------------------------------------------------------------------*)
fun
main () =
let
val args = CommandLine.arguments ()
val (inpf_filename, outf_filename) =
case args of
[] => ("-", "-")
| name :: [] => (name, "-")
| name1 :: name2 :: _ => (name1, name2)
val inpf =
if inpf_filename = "-" then
TextIO.stdIn
else
TextIO.openIn inpf_filename
handle
(IO.Io _) =>
(TextIO.output (TextIO.stdErr, "Failure opening \"");
TextIO.output (TextIO.stdErr, inpf_filename);
TextIO.output (TextIO.stdErr, "\" for input\n");
OS.Process.exit OS.Process.failure)
val outf =
if outf_filename = "-" then
TextIO.stdOut
else
TextIO.openOut outf_filename
handle
(IO.Io _) =>
(TextIO.output (TextIO.stdErr, "Failure opening \"");
TextIO.output (TextIO.stdErr, outf_filename);
TextIO.output (TextIO.stdErr, "\" for output\n");
OS.Process.exit OS.Process.failure)
val inp = Inp.of_instream inpf
in
scan_text (outf, inp)
end
handle Unterminated_comment (line_no, column_no) =>
(TextIO.output (TextIO.stdErr, ": unterminated comment ");
TextIO.output (TextIO.stdErr, "starting at ");
TextIO.output (TextIO.stdErr, Int.toString line_no);
TextIO.output (TextIO.stdErr, ":");
TextIO.output (TextIO.stdErr, Int.toString column_no);
TextIO.output (TextIO.stdErr, "\n");
OS.Process.exit OS.Process.failure)
| Unterminated_character_literal (line_no, column_no) =>
(TextIO.output (TextIO.stdErr, ": unterminated character ");
TextIO.output (TextIO.stdErr, "literal starting at ");
TextIO.output (TextIO.stdErr, Int.toString line_no);
TextIO.output (TextIO.stdErr, ":");
TextIO.output (TextIO.stdErr, Int.toString column_no);
TextIO.output (TextIO.stdErr, "\n");
OS.Process.exit OS.Process.failure)
| Multicharacter_literal (line_no, column_no) =>
(TextIO.output (TextIO.stdErr, ": unsupported multicharacter");
TextIO.output (TextIO.stdErr, " literal starting at ");
TextIO.output (TextIO.stdErr, Int.toString line_no);
TextIO.output (TextIO.stdErr, ":");
TextIO.output (TextIO.stdErr, Int.toString column_no);
TextIO.output (TextIO.stdErr, "\n");
OS.Process.exit OS.Process.failure)
| End_of_input_in_string_literal (line_no, column_no) =>
(TextIO.output (TextIO.stdErr, ": end of input in string");
TextIO.output (TextIO.stdErr, " literal starting at ");
TextIO.output (TextIO.stdErr, Int.toString line_no);
TextIO.output (TextIO.stdErr, ":");
TextIO.output (TextIO.stdErr, Int.toString column_no);
TextIO.output (TextIO.stdErr, "\n");
OS.Process.exit OS.Process.failure)
| End_of_line_in_string_literal (line_no, column_no) =>
(TextIO.output (TextIO.stdErr, ": end of line in string");
TextIO.output (TextIO.stdErr, " literal starting at ");
TextIO.output (TextIO.stdErr, Int.toString line_no);
TextIO.output (TextIO.stdErr, ":");
TextIO.output (TextIO.stdErr, Int.toString column_no);
TextIO.output (TextIO.stdErr, "\n");
OS.Process.exit OS.Process.failure)
| Unsupported_escape (line_no, column_no, c) =>
(TextIO.output (TextIO.stdErr, CommandLine.name ());
TextIO.output (TextIO.stdErr, ": unsupported escape \\");
TextIO.output (TextIO.stdErr, Char.toString c);
TextIO.output (TextIO.stdErr, " at ");
TextIO.output (TextIO.stdErr, Int.toString line_no);
TextIO.output (TextIO.stdErr, ":");
TextIO.output (TextIO.stdErr, Int.toString column_no);
TextIO.output (TextIO.stdErr, "\n");
OS.Process.exit OS.Process.failure)
| Invalid_integer_literal (line_no, column_no, str) =>
(TextIO.output (TextIO.stdErr, CommandLine.name ());
TextIO.output (TextIO.stdErr, ": invalid integer literal ");
TextIO.output (TextIO.stdErr, str);
TextIO.output (TextIO.stdErr, " at ");
TextIO.output (TextIO.stdErr, Int.toString line_no);
TextIO.output (TextIO.stdErr, ":");
TextIO.output (TextIO.stdErr, Int.toString column_no);
TextIO.output (TextIO.stdErr, "\n");
OS.Process.exit OS.Process.failure)
| Unexpected_character (line_no, column_no, c) =>
(TextIO.output (TextIO.stdErr, CommandLine.name ());
TextIO.output (TextIO.stdErr, ": unexpected character '");
TextIO.output (TextIO.stdErr, Char.toString c);
TextIO.output (TextIO.stdErr, "' at ");
TextIO.output (TextIO.stdErr, Int.toString line_no);
TextIO.output (TextIO.stdErr, ":");
TextIO.output (TextIO.stdErr, Int.toString column_no);
TextIO.output (TextIO.stdErr, "\n");
OS.Process.exit OS.Process.failure);
(*------------------------------------------------------------------*)
(* For the Mlton compiler, include the following. For Poly/ML, comment
it out. *)
main ();
(*------------------------------------------------------------------*)
(* Instructions for GNU Emacs. *)
(* local variables: *)
(* mode: sml *)
(* sml-indent-level: 2 *)
(* sml-indent-args: 2 *)
(* end: *)
(*------------------------------------------------------------------*) |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Picat | Picat | main(ARGS) =>
println(ARGS).
main(_) => true. |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #PicoLisp | PicoLisp | #!/usr/bin/picolisp /usr/lib/picolisp/lib.l
(de c ()
(prinl "Got 'c': " (opt)) )
(de h ()
(prinl "Got 'h': " (opt)) )
(load T)
(bye) |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #PL.2FI | PL/I |
/* The entire command line except the command word itself is passed */
/* to the parameter variable in PL/I. */
program: procedure (command_line) options (main);
declare command_line character (100) varying;
...
end program;
|
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #Fish | Fish | v This is the Fish version of the Integer sequence task
>0>:n1+v all comments here
^o" "< still here
And of course here :) |
http://rosettacode.org/wiki/Comments | Comments | Task
Show all ways to include text in a language source file
that's completely ignored by the compiler or interpreter.
Related tasks
Documentation
Here_document
See also
Wikipedia
xkcd (Humor: hand gesture denoting // for "commenting out" people.)
| #Forth | Forth | \ The backslash skips everything else on the line
( The left paren skips everything up to the next right paren on the same line) |
http://rosettacode.org/wiki/Conway%27s_Game_of_Life | Conway's Game of Life | The Game of Life is a cellular automaton devised by the British mathematician John Horton Conway in 1970. It is the best-known example of a cellular automaton.
Conway's game of life is described here:
A cell C is represented by a 1 when alive, or 0 when dead, in an m-by-m (or m×m) square array of cells.
We calculate N - the sum of live cells in C's eight-location neighbourhood, then cell C is alive or dead in the next generation based on the following table:
C N new C
1 0,1 -> 0 # Lonely
1 4,5,6,7,8 -> 0 # Overcrowded
1 2,3 -> 1 # Lives
0 3 -> 1 # It takes three to give birth!
0 0,1,2,4,5,6,7,8 -> 0 # Barren
Assume cells beyond the boundary are always dead.
The "game" is actually a zero-player game, meaning that its evolution is determined by its initial state, needing no input from human players. One interacts with the Game of Life by creating an initial configuration and observing how it evolves.
Task
Although you should test your implementation on more complex examples such as the glider in a larger universe, show the action of the blinker (three adjoining cells in a row all alive), over three generations, in a 3 by 3 grid.
References
Its creator John Conway, explains the game of life. Video from numberphile on youtube.
John Conway Inventing Game of Life - Numberphile video.
Related task
Langton's ant - another well known cellular automaton.
| #MATLAB | MATLAB | life |
http://rosettacode.org/wiki/Conditional_structures | Conditional structures | Control Structures
These are examples of control structures. You may also be interested in:
Conditional structures
Exceptions
Flow-control structures
Loops
Task
List the conditional structures offered by a programming language. See Wikipedia: conditionals for descriptions.
Common conditional structures include if-then-else and switch.
Less common are arithmetic if, ternary operator and Hash-based conditionals.
Arithmetic if allows tight control over computed gotos, which optimizers have a hard time to figure out.
| #Erlang | Erlang | case X of
{N,M} when N > M -> M;
{N,M} when N < M -> N;
_ -> equal
end. |
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #VBA | VBA |
Private Function IsEqualOrAscending(myList) As String
Dim i&, boolEqual As Boolean, boolAsc As Boolean
On Error Resume Next
If UBound(myList) > 0 Then
If Err.Number > 0 Then
IsEqualOrAscending = "Error " & Err.Number & " : Empty array"
On Error GoTo 0
Exit Function
Else
For i = 1 To UBound(myList)
If myList(i) <> myList(i - 1) Then boolEqual = True
If myList(i) <= myList(i - 1) Then boolAsc = True
Next
End If
End If
IsEqualOrAscending = "List : " & Join(myList, ",") & ", IsEqual : " & (Not boolEqual) & ", IsAscending : " & Not boolAsc
End Function
|
http://rosettacode.org/wiki/Compare_a_list_of_strings | Compare a list of strings | Task
Given a list of arbitrarily many strings, show how to:
test if they are all lexically equal
test if every string is lexically less than the one after it (i.e. whether the list is in strict ascending order)
Each of those two tests should result in a single true or false value, which could be used as the condition of an if statement or similar.
If the input list has less than two elements, the tests should always return true.
There is no need to provide a complete program and output.
Assume that the strings are already stored in an array/list/sequence/tuple variable (whatever is most idiomatic) with the name strings, and just show the expressions for performing those two tests on it (plus of course any includes and custom functions etc. that it needs), with as little distractions as possible.
Try to write your solution in a way that does not modify the original list, but if it does then please add a note to make that clear to readers.
If you need further guidance/clarification, see #Perl and #Python for solutions that use implicit short-circuiting loops, and #Raku for a solution that gets away with simply using a built-in language feature.
Other tasks related to string operations:
Metrics
Array length
String length
Copy a string
Empty string (assignment)
Counting
Word frequency
Letter frequency
Jewels and stones
I before E except after C
Bioinformatics/base count
Count occurrences of a substring
Count how many vowels and consonants occur in a string
Remove/replace
XXXX redacted
Conjugate a Latin verb
Remove vowels from a string
String interpolation (included)
Strip block comments
Strip comments from a string
Strip a set of characters from a string
Strip whitespace from a string -- top and tail
Strip control codes and extended characters from a string
Anagrams/Derangements/shuffling
Word wheel
ABC problem
Sattolo cycle
Knuth shuffle
Ordered words
Superpermutation minimisation
Textonyms (using a phone text pad)
Anagrams
Anagrams/Deranged anagrams
Permutations/Derangements
Find/Search/Determine
ABC words
Odd words
Word ladder
Semordnilap
Word search
Wordiff (game)
String matching
Tea cup rim text
Alternade words
Changeable words
State name puzzle
String comparison
Unique characters
Unique characters in each string
Extract file extension
Levenshtein distance
Palindrome detection
Common list elements
Longest common suffix
Longest common prefix
Compare a list of strings
Longest common substring
Find common directory path
Words from neighbour ones
Change e letters to i in words
Non-continuous subsequences
Longest common subsequence
Longest palindromic substrings
Longest increasing subsequence
Words containing "the" substring
Sum of the digits of n is substring of n
Determine if a string is numeric
Determine if a string is collapsible
Determine if a string is squeezable
Determine if a string has all unique characters
Determine if a string has all the same characters
Longest substrings without repeating characters
Find words which contains all the vowels
Find words which contains most consonants
Find words which contains more than 3 vowels
Find words which first and last three letters are equals
Find words which odd letters are consonants and even letters are vowels or vice_versa
Formatting
Substring
Rep-string
Word wrap
String case
Align columns
Literals/String
Repeat a string
Brace expansion
Brace expansion using ranges
Reverse a string
Phrase reversals
Comma quibbling
Special characters
String concatenation
Substring/Top and tail
Commatizing numbers
Reverse words in a string
Suffixation of decimal numbers
Long literals, with continuations
Numerical and alphabetical suffixes
Abbreviations, easy
Abbreviations, simple
Abbreviations, automatic
Song lyrics/poems/Mad Libs/phrases
Mad Libs
Magic 8-ball
99 Bottles of Beer
The Name Game (a song)
The Old lady swallowed a fly
The Twelve Days of Christmas
Tokenize
Text between
Tokenize a string
Word break problem
Tokenize a string with escaping
Split a character string based on change of character
Sequences
Show ASCII table
De Bruijn sequences
Self-referential sequences
Generate lower case ASCII alphabet
| #VBScript | VBScript |
Function string_compare(arr)
lexical = "Pass"
ascending = "Pass"
For i = 0 To UBound(arr)
If i+1 <= UBound(arr) Then
If arr(i) <> arr(i+1) Then
lexical = "Fail"
End If
If arr(i) >= arr(i+1) Then
ascending = "Fail"
End If
End If
Next
string_compare = "List: " & Join(arr,",") & vbCrLf &_
"Lexical Test: " & lexical & vbCrLf &_
"Ascending Test: " & ascending & vbCrLf
End Function
WScript.StdOut.WriteLine string_compare(Array("AA","BB","CC"))
WScript.StdOut.WriteLine string_compare(Array("AA","AA","AA"))
WScript.StdOut.WriteLine string_compare(Array("AA","CC","BB"))
WScript.StdOut.WriteLine string_compare(Array("AA","ACB","BB","CC"))
WScript.StdOut.WriteLine string_compare(Array("FF"))
|
http://rosettacode.org/wiki/Comma_quibbling | Comma quibbling | Comma quibbling is a task originally set by Eric Lippert in his blog.
Task
Write a function to generate a string output which is the concatenation of input words from a list/sequence where:
An input of no words produces the output string of just the two brace characters "{}".
An input of just one word, e.g. ["ABC"], produces the output string of the word inside the two braces, e.g. "{ABC}".
An input of two words, e.g. ["ABC", "DEF"], produces the output string of the two words inside the two braces with the words separated by the string " and ", e.g. "{ABC and DEF}".
An input of three or more words, e.g. ["ABC", "DEF", "G", "H"], produces the output string of all but the last word separated by ", " with the last word separated by " and " and all within braces; e.g. "{ABC, DEF, G and H}".
Test your function with the following series of inputs showing your output here on this page:
[] # (No input words).
["ABC"]
["ABC", "DEF"]
["ABC", "DEF", "G", "H"]
Note: Assume words are non-empty strings of uppercase characters for this task.
| #Objeck | Objeck | class Quibbler {
function : Quibble(words : String[]) ~ String {
text := "{";
each(i : words) {
text += words[i];
if(i < words->Size() - 2) {
text += ", ";
}
else if(i = words->Size() - 2) {
text += " and ";
};
};
text += "}";
return text;
}
function : Main(args : String[]) ~ Nil {
words := String->New[0];
Quibble(words)->PrintLine();
words := ["ABC"];
Quibble(words)->PrintLine();
words := ["ABC", "DEF"];
Quibble(words)->PrintLine();
words := ["ABC", "DEF", "G", "H"];
Quibble(words)->PrintLine();
}
} |
http://rosettacode.org/wiki/Combinations_with_repetitions | Combinations with repetitions | The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of those sets is chosen from
S
{\displaystyle S}
.
In the real world, it is about choosing sets where there is a “large” supply of each type of element and where the order of choice does not matter.
For example:
Q: How many ways can a person choose two doughnuts from a store selling three types of doughnut: iced, jam, and plain? (i.e.,
S
{\displaystyle S}
is
{
i
c
e
d
,
j
a
m
,
p
l
a
i
n
}
{\displaystyle \{\mathrm {iced} ,\mathrm {jam} ,\mathrm {plain} \}}
,
|
S
|
=
3
{\displaystyle |S|=3}
, and
k
=
2
{\displaystyle k=2}
.)
A: 6: {iced, iced}; {iced, jam}; {iced, plain}; {jam, jam}; {jam, plain}; {plain, plain}.
Note that both the order of items within a pair, and the order of the pairs given in the answer is not significant; the pairs represent multisets.
Also note that doughnut can also be spelled donut.
Task
Write a function/program/routine/.. to generate all the combinations with repetitions of
n
{\displaystyle n}
types of things taken
k
{\displaystyle k}
at a time and use it to show an answer to the doughnut example above.
For extra credit, use the function to compute and show just the number of ways of choosing three doughnuts from a choice of ten types of doughnut. Do not show the individual choices for this part.
References
k-combination with repetitions
See also
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #Swift | Swift | func combosWithRep<T>(var objects: [T], n: Int) -> [[T]] {
if n == 0 { return [[]] } else {
var combos = [[T]]()
while let element = objects.last {
combos.appendContentsOf(combosWithRep(objects, n: n - 1).map{ $0 + [element] })
objects.removeLast()
}
return combos
}
}
print(combosWithRep(["iced", "jam", "plain"], n: 2).map {$0.joinWithSeparator(" and ")}.joinWithSeparator("\n")) |
http://rosettacode.org/wiki/Combinations_with_repetitions | Combinations with repetitions | The set of combinations with repetitions is computed from a set,
S
{\displaystyle S}
(of cardinality
n
{\displaystyle n}
), and a size of resulting selection,
k
{\displaystyle k}
, by reporting the sets of cardinality
k
{\displaystyle k}
where each member of those sets is chosen from
S
{\displaystyle S}
.
In the real world, it is about choosing sets where there is a “large” supply of each type of element and where the order of choice does not matter.
For example:
Q: How many ways can a person choose two doughnuts from a store selling three types of doughnut: iced, jam, and plain? (i.e.,
S
{\displaystyle S}
is
{
i
c
e
d
,
j
a
m
,
p
l
a
i
n
}
{\displaystyle \{\mathrm {iced} ,\mathrm {jam} ,\mathrm {plain} \}}
,
|
S
|
=
3
{\displaystyle |S|=3}
, and
k
=
2
{\displaystyle k=2}
.)
A: 6: {iced, iced}; {iced, jam}; {iced, plain}; {jam, jam}; {jam, plain}; {plain, plain}.
Note that both the order of items within a pair, and the order of the pairs given in the answer is not significant; the pairs represent multisets.
Also note that doughnut can also be spelled donut.
Task
Write a function/program/routine/.. to generate all the combinations with repetitions of
n
{\displaystyle n}
types of things taken
k
{\displaystyle k}
at a time and use it to show an answer to the doughnut example above.
For extra credit, use the function to compute and show just the number of ways of choosing three doughnuts from a choice of ten types of doughnut. Do not show the individual choices for this part.
References
k-combination with repetitions
See also
The number of samples of size k from n objects.
With combinations and permutations generation tasks.
Order Unimportant
Order Important
Without replacement
(
n
k
)
=
n
C
k
=
n
(
n
−
1
)
…
(
n
−
k
+
1
)
k
(
k
−
1
)
…
1
{\displaystyle {\binom {n}{k}}=^{n}\operatorname {C} _{k}={\frac {n(n-1)\ldots (n-k+1)}{k(k-1)\dots 1}}}
n
P
k
=
n
⋅
(
n
−
1
)
⋅
(
n
−
2
)
⋯
(
n
−
k
+
1
)
{\displaystyle ^{n}\operatorname {P} _{k}=n\cdot (n-1)\cdot (n-2)\cdots (n-k+1)}
Task: Combinations
Task: Permutations
With replacement
(
n
+
k
−
1
k
)
=
n
+
k
−
1
C
k
=
(
n
+
k
−
1
)
!
(
n
−
1
)
!
k
!
{\displaystyle {\binom {n+k-1}{k}}=^{n+k-1}\operatorname {C} _{k}={(n+k-1)! \over (n-1)!k!}}
n
k
{\displaystyle n^{k}}
Task: Combinations with repetitions
Task: Permutations with repetitions
| #Tcl | Tcl | package require Tcl 8.5
proc combrepl {set n {presorted no}} {
if {!$presorted} {
set set [lsort $set]
}
if {[incr n 0] < 1} {
return {}
} elseif {$n < 2} {
return $set
}
# Recursive call
set res [combrepl $set [incr n -1] yes]
set result {}
foreach item $set {
foreach inner $res {
dict set result [lsort [list $item {*}$inner]] {}
}
}
return [dict keys $result]
}
puts [combrepl {iced jam plain} 2]
puts [llength [combrepl {1 2 3 4 5 6 7 8 9 10} 3]] |
http://rosettacode.org/wiki/Compiler/lexical_analyzer | Compiler/lexical analyzer | Definition from Wikipedia:
Lexical analysis is the process of converting a sequence of characters (such as in a computer program or web page) into a sequence of tokens (strings with an identified "meaning"). A program that performs lexical analysis may be called a lexer, tokenizer, or scanner (though "scanner" is also used to refer to the first stage of a lexer).
Task[edit]
Create a lexical analyzer for the simple programming language specified below. The
program should read input from a file and/or stdin, and write output to a file and/or
stdout. If the language being used has a lexer module/library/class, it would be great
if two versions of the solution are provided: One without the lexer module, and one with.
Input Specification
The simple programming language to be analyzed is more or less a subset of C. It supports the following tokens:
Operators
Name
Common name
Character sequence
Op_multiply
multiply
*
Op_divide
divide
/
Op_mod
mod
%
Op_add
plus
+
Op_subtract
minus
-
Op_negate
unary minus
-
Op_less
less than
<
Op_lessequal
less than or equal
<=
Op_greater
greater than
>
Op_greaterequal
greater than or equal
>=
Op_equal
equal
==
Op_notequal
not equal
!=
Op_not
unary not
!
Op_assign
assignment
=
Op_and
logical and
&&
Op_or
logical or
¦¦
The - token should always be interpreted as Op_subtract by the lexer. Turning some Op_subtract into Op_negate will be the job of the syntax analyzer, which is not part of this task.
Symbols
Name
Common name
Character
LeftParen
left parenthesis
(
RightParen
right parenthesis
)
LeftBrace
left brace
{
RightBrace
right brace
}
Semicolon
semi-colon
;
Comma
comma
,
Keywords
Name
Character sequence
Keyword_if
if
Keyword_else
else
Keyword_while
while
Keyword_print
print
Keyword_putc
putc
Identifiers and literals
These differ from the the previous tokens, in that each occurrence of them has a value associated with it.
Name
Common name
Format description
Format regex
Value
Identifier
identifier
one or more letter/number/underscore characters, but not starting with a number
[_a-zA-Z][_a-zA-Z0-9]*
as is
Integer
integer literal
one or more digits
[0-9]+
as is, interpreted as a number
Integer
char literal
exactly one character (anything except newline or single quote) or one of the allowed escape sequences, enclosed by single quotes
'([^'\n]|\\n|\\\\)'
the ASCII code point number of the character, e.g. 65 for 'A' and 10 for '\n'
String
string literal
zero or more characters (anything except newline or double quote), enclosed by double quotes
"[^"\n]*"
the characters without the double quotes and with escape sequences converted
For char and string literals, the \n escape sequence is supported to represent a new-line character.
For char and string literals, to represent a backslash, use \\.
No other special sequences are supported. This means that:
Char literals cannot represent a single quote character (value 39).
String literals cannot represent strings containing double quote characters.
Zero-width tokens
Name
Location
End_of_input
when the end of the input stream is reached
White space
Zero or more whitespace characters, or comments enclosed in /* ... */, are allowed between any two tokens, with the exceptions noted below.
"Longest token matching" is used to resolve conflicts (e.g., in order to match <= as a single token rather than the two tokens < and =).
Whitespace is required between two tokens that have an alphanumeric character or underscore at the edge.
This means: keywords, identifiers, and integer literals.
e.g. ifprint is recognized as an identifier, instead of the keywords if and print.
e.g. 42fred is invalid, and neither recognized as a number nor an identifier.
Whitespace is not allowed inside of tokens (except for chars and strings where they are part of the value).
e.g. & & is invalid, and not interpreted as the && operator.
For example, the following two program fragments are equivalent, and should produce the same token stream except for the line and column positions:
if ( p /* meaning n is prime */ ) {
print ( n , " " ) ;
count = count + 1 ; /* number of primes found so far */
}
if(p){print(n," ");count=count+1;}
Complete list of token names
End_of_input Op_multiply Op_divide Op_mod Op_add Op_subtract
Op_negate Op_not Op_less Op_lessequal Op_greater Op_greaterequal
Op_equal Op_notequal Op_assign Op_and Op_or Keyword_if
Keyword_else Keyword_while Keyword_print Keyword_putc LeftParen RightParen
LeftBrace RightBrace Semicolon Comma Identifier Integer
String
Output Format
The program output should be a sequence of lines, each consisting of the following whitespace-separated fields:
the line number where the token starts
the column number where the token starts
the token name
the token value (only for Identifier, Integer, and String tokens)
the number of spaces between fields is up to you. Neatly aligned is nice, but not a requirement.
This task is intended to be used as part of a pipeline, with the other compiler tasks - for example:
lex < hello.t | parse | gen | vm
Or possibly:
lex hello.t lex.out
parse lex.out parse.out
gen parse.out gen.out
vm gen.out
This implies that the output of this task (the lexical analyzer) should be suitable as input to any of the Syntax Analyzer task programs.
Diagnostics
The following error conditions should be caught:
Error
Example
Empty character constant
''
Unknown escape sequence.
\r
Multi-character constant.
'xx'
End-of-file in comment. Closing comment characters not found.
End-of-file while scanning string literal. Closing string character not found.
End-of-line while scanning string literal. Closing string character not found before end-of-line.
Unrecognized character.
|
Invalid number. Starts like a number, but ends in non-numeric characters.
123abc
Test Cases
Input
Output
Test Case 1:
/*
Hello world
*/
print("Hello, World!\n");
4 1 Keyword_print
4 6 LeftParen
4 7 String "Hello, World!\n"
4 24 RightParen
4 25 Semicolon
5 1 End_of_input
Test Case 2:
/*
Show Ident and Integers
*/
phoenix_number = 142857;
print(phoenix_number, "\n");
4 1 Identifier phoenix_number
4 16 Op_assign
4 18 Integer 142857
4 24 Semicolon
5 1 Keyword_print
5 6 LeftParen
5 7 Identifier phoenix_number
5 21 Comma
5 23 String "\n"
5 27 RightParen
5 28 Semicolon
6 1 End_of_input
Test Case 3:
/*
All lexical tokens - not syntactically correct, but that will
have to wait until syntax analysis
*/
/* Print */ print /* Sub */ -
/* Putc */ putc /* Lss */ <
/* If */ if /* Gtr */ >
/* Else */ else /* Leq */ <=
/* While */ while /* Geq */ >=
/* Lbrace */ { /* Eq */ ==
/* Rbrace */ } /* Neq */ !=
/* Lparen */ ( /* And */ &&
/* Rparen */ ) /* Or */ ||
/* Uminus */ - /* Semi */ ;
/* Not */ ! /* Comma */ ,
/* Mul */ * /* Assign */ =
/* Div */ / /* Integer */ 42
/* Mod */ % /* String */ "String literal"
/* Add */ + /* Ident */ variable_name
/* character literal */ '\n'
/* character literal */ '\\'
/* character literal */ ' '
5 16 Keyword_print
5 40 Op_subtract
6 16 Keyword_putc
6 40 Op_less
7 16 Keyword_if
7 40 Op_greater
8 16 Keyword_else
8 40 Op_lessequal
9 16 Keyword_while
9 40 Op_greaterequal
10 16 LeftBrace
10 40 Op_equal
11 16 RightBrace
11 40 Op_notequal
12 16 LeftParen
12 40 Op_and
13 16 RightParen
13 40 Op_or
14 16 Op_subtract
14 40 Semicolon
15 16 Op_not
15 40 Comma
16 16 Op_multiply
16 40 Op_assign
17 16 Op_divide
17 40 Integer 42
18 16 Op_mod
18 40 String "String literal"
19 16 Op_add
19 40 Identifier variable_name
20 26 Integer 10
21 26 Integer 92
22 26 Integer 32
23 1 End_of_input
Test Case 4:
/*** test printing, embedded \n and comments with lots of '*' ***/
print(42);
print("\nHello World\nGood Bye\nok\n");
print("Print a slash n - \\n.\n");
2 1 Keyword_print
2 6 LeftParen
2 7 Integer 42
2 9 RightParen
2 10 Semicolon
3 1 Keyword_print
3 6 LeftParen
3 7 String "\nHello World\nGood Bye\nok\n"
3 38 RightParen
3 39 Semicolon
4 1 Keyword_print
4 6 LeftParen
4 7 String "Print a slash n - \\n.\n"
4 33 RightParen
4 34 Semicolon
5 1 End_of_input
Additional examples
Your solution should pass all the test cases above and the additional tests found Here.
Reference
The C and Python versions can be considered reference implementations.
Related Tasks
Syntax Analyzer task
Code Generator task
Virtual Machine Interpreter task
AST Interpreter task
| #Wren | Wren | import "/dynamic" for Enum, Struct, Tuple
import "/str" for Char
import "/fmt" for Fmt
import "/ioutil" for FileUtil
import "os" for Process
var tokens = [
"EOI",
"Mul",
"Div",
"Mod",
"Add",
"Sub",
"Negate",
"Not",
"Lss",
"Leq",
"Gtr",
"Geq",
"Eq",
"Neq",
"Assign",
"And",
"Or",
"If",
"Else",
"While",
"Print",
"Putc",
"Lparen",
"Rparen",
"Lbrace",
"Rbrace",
"Semi",
"Comma",
"Ident",
"Integer",
"String"
]
var Token = Enum.create("Token", tokens)
var TokData = Struct.create("TokData", ["eline", "ecol", "tok", "v"])
var Symbol = Tuple.create("Symbol", ["name", "tok"])
// symbol table
var symtab = []
var curLine = ""
var curCh = ""
var lineNum = 0
var colNum = 0
var etx = 4 // used to signify EOI
var lines = []
var lineCount = 0
var errorMsg = Fn.new { |eline, ecol, msg| Fiber.abort("(%(eline):%(ecol)) %(msg)") }
// add an identifier to the symbpl table
var install = Fn.new { |name, tok|
var sym = Symbol.new(name, tok)
symtab.add(sym)
}
// search for an identifier in the symbol table
var lookup = Fn.new { |name|
for (i in 0...symtab.count) {
if (symtab[i].name == name) return i
}
return -1
}
// read the next line of input from the source file
var nextLine // recursive function
nextLine = Fn.new {
if (lineNum == lineCount) {
curCh = etx
curLine = ""
colNum = 1
return
}
curLine = lines[lineNum]
lineNum = lineNum + 1
colNum = 0
if (curLine == "") nextLine.call() // skip blank lines
}
// get the next char
var nextChar = Fn.new {
if (colNum >= curLine.count) nextLine.call()
if (colNum < curLine.count) {
curCh = curLine[colNum]
colNum = colNum + 1
}
}
var follow = Fn.new { |eline, ecol, expect, ifyes, ifno|
if (curCh == expect) {
nextChar.call()
return ifyes
}
if (ifno == Token.EOI) {
errorMsg.call(eline, ecol, "follow unrecognized character: " + curCh)
}
return ifno
}
var getTok // recursive function
getTok = Fn.new {
// skip whitespace
while (curCh == " " || curCh == "\t" || curCh == "\n") nextChar.call()
var td = TokData.new(lineNum, colNum, 0, "")
if (curCh == etx) {
td.tok = Token.EOI
return td
}
if (curCh == "{") {
td.tok = Token.Lbrace
nextChar.call()
return td
}
if (curCh == "}") {
td.tok = Token.Rbrace
nextChar.call()
return td
}
if (curCh == "(") {
td.tok = Token.Lparen
nextChar.call()
return td
}
if (curCh == ")") {
td.tok = Token.Rparen
nextChar.call()
return td
}
if (curCh == "+") {
td.tok = Token.Add
nextChar.call()
return td
}
if (curCh == "-") {
td.tok = Token.Sub
nextChar.call()
return td
}
if (curCh == "*") {
td.tok = Token.Mul
nextChar.call()
return td
}
if (curCh == "\%") {
td.tok = Token.Mod
nextChar.call()
return td
}
if (curCh == ";") {
td.tok = Token.Semi
nextChar.call()
return td
}
if (curCh == ",") {
td.tok = Token.Comma
nextChar.call()
return td
}
if (curCh == "'") { // single char literals
nextChar.call()
td.v = curCh.bytes[0].toString
if (curCh == "'") {
errorMsg.call(td.eline, td.ecol, "Empty character constant")
}
if (curCh == "\\") {
nextChar.call()
if (curCh == "n") {
td.v = "10"
} else if (curCh == "\\") {
td.v = "92"
} else {
errorMsg.call(td.eline, td.ecol, "unknown escape sequence: "+ curCh)
}
}
nextChar.call()
if (curCh != "'") {
errorMsg.call(td.eline, td.ecol, "multi-character constant")
}
nextChar.call()
td.tok = Token.Integer
return td
}
if (curCh == "<") {
nextChar.call()
td.tok = follow.call(td.eline, td.ecol, "=", Token.Leq, Token.Lss)
return td
}
if (curCh == ">") {
nextChar.call()
td.tok = follow.call(td.eline, td.ecol, "=", Token.Geq, Token.Gtr)
return td
}
if (curCh == "!") {
nextChar.call()
td.tok = follow.call(td.eline, td.ecol, "=", Token.Neq, Token.Not)
return td
}
if (curCh == "=") {
nextChar.call()
td.tok = follow.call(td.eline, td.ecol, "=", Token.Eq, Token.Assign)
return td
}
if (curCh == "&") {
nextChar.call()
td.tok = follow.call(td.eline, td.ecol, "&", Token.And, Token.EOI)
return td
}
if (curCh == "|") {
nextChar.call()
td.tok = follow.call(td.eline, td.ecol, "|", Token.Or, Token.EOI)
return td
}
if (curCh == "\"") { // string
td.v = curCh
nextChar.call()
while (curCh != "\"") {
if (curCh == "\n") {
errorMsg.call(td.eline, td.ecol, "EOL in string")
}
if (curCh == etx) {
errorMsg.call(td.eline, td.ecol, "EOF in string")
}
td.v = td.v + curCh
nextChar.call()
}
td.v = td.v + curCh
nextChar.call()
td.tok = Token.String
return td
}
if (curCh == "/") { // div or comment
nextChar.call()
if (curCh != "*") {
td.tok = Token.Div
return td
}
// skip comments
nextChar.call()
while (true) {
if (curCh == "*") {
nextChar.call()
if (curCh == "/") {
nextChar.call()
return getTok.call()
}
} else if (curCh == etx) {
errorMsg.call(td.eline, td.ecol, "EOF in comment")
} else {
nextChar.call()
}
}
}
//integers or identifiers
var isNumber = Char.isDigit(curCh)
td.v = ""
while (Char.isAsciiAlphaNum(curCh) || curCh == "_") {
if (!Char.isDigit(curCh)) isNumber = false
td.v = td.v + curCh
nextChar.call()
}
if (td.v.count == 0) {
errorMsg.call(td.eline, td.ecol, "unknown character: " + curCh)
}
if (Char.isDigit(td.v[0])) {
if (!isNumber) {
errorMsg.call(td.eline, td.ecol, "invalid number: " + curCh)
}
td.tok = Token.Integer
return td
}
var index = lookup.call(td.v)
td.tok = (index == -1) ? Token.Ident : symtab[index].tok
return td
}
var initLex = Fn.new {
install.call("else", Token.Else)
install.call("if", Token.If)
install.call("print", Token.Print)
install.call("putc", Token.Putc)
install.call("while", Token.While)
nextChar.call()
}
var process = Fn.new {
var tokMap = {}
tokMap[Token.EOI] = "End_of_input"
tokMap[Token.Mul] = "Op_multiply"
tokMap[Token.Div] = "Op_divide"
tokMap[Token.Mod] = "Op_mod"
tokMap[Token.Add] = "Op_add"
tokMap[Token.Sub] = "Op_subtract"
tokMap[Token.Negate] = "Op_negate"
tokMap[Token.Not] = "Op_not"
tokMap[Token.Lss] = "Op_less"
tokMap[Token.Leq] = "Op_lessequal"
tokMap[Token.Gtr] = "Op_greater"
tokMap[Token.Geq] = "Op_greaterequal"
tokMap[Token.Eq] = "Op_equal"
tokMap[Token.Neq] = "Op_notequal"
tokMap[Token.Assign] = "Op_assign"
tokMap[Token.And] = "Op_and"
tokMap[Token.Or] = "Op_or"
tokMap[Token.If] = "Keyword_if"
tokMap[Token.Else] = "Keyword_else"
tokMap[Token.While] = "Keyword_while"
tokMap[Token.Print] = "Keyword_print"
tokMap[Token.Putc] = "Keyword_putc"
tokMap[Token.Lparen] = "LeftParen"
tokMap[Token.Rparen] = "RightParen"
tokMap[Token.Lbrace] = "LeftBrace"
tokMap[Token.Rbrace] = "RightBrace"
tokMap[Token.Semi] = "Semicolon"
tokMap[Token.Comma] = "Comma"
tokMap[Token.Ident] = "Identifier"
tokMap[Token.Integer] = "Integer"
tokMap[Token.String] = "String"
while (true) {
var td = getTok.call()
Fmt.write("$5d $5d $-16s", td.eline, td.ecol, tokMap[td.tok])
if (td.tok == Token.Integer || td.tok == Token.Ident || td.tok == Token.String) {
System.print(td.v)
} else {
System.print()
}
if (td.tok == Token.EOI) return
}
}
var args = Process.arguments
if (args.count == 0) {
System.print("Filename required")
return
}
lines = FileUtil.readLines(args[0])
lineCount = lines.count
initLex.call()
process.call() |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #Pop11 | Pop11 | lvars arg;
for arg in poparglist do
printf(arg, '->%s<-\n');
endfor; |
http://rosettacode.org/wiki/Command-line_arguments | Command-line arguments | Command-line arguments is part of Short Circuit's Console Program Basics selection.
Scripted main
See also Program name.
For parsing command line arguments intelligently, see Parsing command-line arguments.
Example command line:
myprogram -c "alpha beta" -h "gamma"
| #PowerBASIC | PowerBASIC | ? "args: '"; COMMAND$; "'" |
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