anchor.diff:  |LIST 100+ |Lists line 100 and the next 20 lines.
   |==========
   
  -LOAD
  -~~~~
  -
  -Loads a stored program into memory.
  -Sorts statements by line number.
  -Clears the current program prior to loading the new one.
  -
  -Syntax:	LOAD filename
  -
  -The 'filename' argument must be enclosed in quotes.
  -
  -Clears all breakpoints.
  -
  -NEW
  -~~~
  -
  -Clears the current program.
  -Does not ask to save a loaded program.
  -
  -Syntax:	NEW
  -
  -Clears all breakpoints.
  -
  -PRETTY
  -~~~~~~
  -
  -Lists the current program on the screen, adjusting the spacing between keywords, variable names, and constants.
  -
  -Syntax:	PRETTY [line specification]
  -
  -The line specification is the same as the line specification for the LIST command.
  -
  -PROFILE
  -~~~~~~~
  -
  -Lists the current program on the screen in "pretty" mode, with additional information about the most recent run.
  -The profile information is enclosed in parentheses immediately after line numbers.
  -
  -The line
  -
  -    10 LET A = 10
  -
  -will appear in the profile as
  -
  -    10 (0.0005/1) LET A = 10
  -
  -
  -Syntax:	PROFILE [line specification]
  -
  -The line specification is the same as the line specification for the LIST and PRETTY commands.
  -
  -The profile information lists the total execution time for the statement, and the number of times the statement was executed.
  -Counts are reset at the start of each execution.
  -
  -Profiling excludes the first phase of processing of certain lines (DATA, FILES, and DEF FN).
  -These lines are processed before the program begins, and they do nothing when executed in the main execution.
  -For example, placing a DATA statement inside of a FOR/NEXT loop does not cause the lines data values to be stored multiple times.
  -
  -RENUMBER
  -~~~~~~~~
  -
  -Renumbers lines in the current program.
  -
  -Syntax: RENUMBER
  -
  -Modifies the current program, changing each line number.
  -The first line is assigned line number 10.
  -Each successive line is assgned a number 10 higher than the previous line.
  -
  -Each statement which contains a line number (GOTO, GOSUB, IF) is modified to use the corresponding new line number.
  -
  -RENUMBER also adjusts breakpoints, if any are set.
  -
   RUN
   ~~~
   
  
positive.code: 
  The second phase executes statements, starting with the lowest-numbered statement and following the path of execution.
  
  SAVE
  ~~~~
  
  Saves the current program to disk.
  Will overwrite an existing file without prompting.
  
  Syntax:	SAVE filename
  
  The 'filename' argument must be enclosed in quotes.
  
  TOKENS
  ~~~~~~
  
negative.code: They have no line number.
  They are available only in "run" mode.
  
  LOAD
  ~~~~
  
  Loads a stored program into memory.
  Sorts statements by line number.
  Clears the current program prior to loading the new one.
  
  Syntax:	LOAD filename
  
  The 'filename' argument must be enclosed in quotes.
  
  Clears all breakpoints.
  
  SAVE
  ~~~~
  
  Saves the current program to disk.
  Will overwrite an existing file without prompting.
  
  Syntax:	SAVE filename
  
  The 'filename' argument must be enclosed in quotes.
  
  NEW
  ~~~
  
  Clears the current program.
  Does not ask to save a loaded program.
  
  Syntax:	NEW
  
  Clears all breakpoints.
  
  LIST
  ~~~~
  