+USING: help.markup help.syntax kernel math sequences
+quotations ;
 IN: deques
-USING: help.markup help.syntax kernel ;
-
-ARTICLE: "deques" "Dequeues"
-"A deque is a data structure with constant-time insertion and removal of elements at both ends. Dequeue operations are defined in the " { $vocab-link "deques" } " vocabulary."
-$nl
-"Dequeues must be instances of a mixin class:"
-{ $subsection deque }
-"Dequeues must implement a protocol."
-$nl
-"Querying the deque:"
-{ $subsection peek-front }
-{ $subsection peek-back }
-{ $subsection deque-length }
-{ $subsection deque-member? }
-"Adding and removing elements:"
-{ $subsection push-front* }
-{ $subsection push-back* }
-{ $subsection pop-front* }
-{ $subsection pop-back* }
-{ $subsection clear-deque }
-"Working with node objects output by " { $link push-front* } " and " { $link push-back* } ":"
-{ $subsection delete-node }
-{ $subsection node-value }
-"Utility operations built in terms of the above:"
-{ $subsection deque-empty? }
-{ $subsection push-front }
-{ $subsection push-all-front }
-{ $subsection push-back }
-{ $subsection push-all-back }
-{ $subsection pop-front }
-{ $subsection pop-back }
-{ $subsection slurp-deque }
-"When using a deque as a queue, the convention is to queue elements with " { $link push-front } " and deque them with " { $link pop-back } "." ;
-
-ABOUT: "deques"
 
 HELP: deque-empty?
-{ $values { "deque" { $link deque } } { "?" "a boolean" } }
+{ $values { "deque" deque } { "?" "a boolean" } }
 { $description "Returns true if a deque is empty." }
 { $notes "This operation is O(1)." } ;
+
+HELP: clear-deque
+{ $values
+     { "deque" deque } }
+{ $description "Removes all elements from a deque." } ;
+
+HELP: deque-length
+{ $values
+     { "deque" deque }
+     { "n" integer } }
+{ $description "Returns the number of elements in a deque." } ;
+
+HELP: deque-member?
+{ $values
+     { "value" object } { "deque" deque }
+     { "?" "a boolean" } }
+{ $description "Returns true if the " { $snippet "value" } " is found in the deque." } ;
 
 HELP: push-front
 { $values { "obj" object } { "deque" deque } }

{ $values { "obj" object } { "deque" deque } { "node" "a node" } }
{ $description "Push the object onto the back of the deque and return the newly created node." } 
{ $notes "This operation is O(1)." } ;

HELP: peek-front
{ $values { "deque" deque } { "obj" object } }

{ $values { "deque" deque } }
{ $description "Pop the object off the back of the deque." }
{ $notes "This operation is O(1)." } ;

HELP: delete-node
{ $values
     { "node" object } { "deque" deque } }
{ $description "Deletes the node from the deque." } ;

HELP: deque
{ $description "A data structure that has constant-time insertion and removal of elements at both ends." } ;

HELP: node-value
{ $values
     { "node" object }
     { "value" object } }
{ $description "Accesses the value stored at a node." } ;

HELP: slurp-deque
{ $values
     { "deque" deque } { "quot" quotation } }
{ $description "Pops off the back element of the deque and calls the quotation in a loop until the deque is empty." } ;

ARTICLE: "deques" "Deques"
"The " { $vocab-link "deques" } " vocabulary implements the deque data structure which has constant-time insertion and removal of elements at both ends."
$nl
"Deques must be instances of a mixin class:"
{ $subsection deque }
"Deques must implement a protocol."
$nl
"Querying the deque:"
{ $subsection peek-front }
{ $subsection peek-back }
{ $subsection deque-length }
{ $subsection deque-member? }
"Adding and removing elements:"
{ $subsection push-front* }
{ $subsection push-back* }
{ $subsection pop-front* }
{ $subsection pop-back* }
{ $subsection clear-deque }
"Working with node objects output by " { $link push-front* } " and " { $link push-back* } ":"
{ $subsection delete-node }
{ $subsection node-value }
"Utility operations built in terms of the above:"
{ $subsection deque-empty? }
{ $subsection push-front }
{ $subsection push-all-front }
{ $subsection push-back }
{ $subsection push-all-back }
{ $subsection pop-front }
{ $subsection pop-back }
{ $subsection slurp-deque }
"When using a deque as a queue, the convention is to queue elements with " { $link push-front } " and deque them with " { $link pop-back } "." ;

ABOUT: "deques"
