78 lines
2.3 KiB
Factor
78 lines
2.3 KiB
Factor
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USING: help.markup help.syntax kernel ;
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IN: queues
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ARTICLE: "queues" "Queues"
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"Last-in-first-out queues are defined in the " { $vocab-link "queues" } " vocabulary."
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$nl
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"Queues are a class."
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{ $subsection queue }
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{ $subsection queue? }
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{ $subsection <queue> }
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"Testing queues:"
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{ $subsection queue-empty? }
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"Adding elements:"
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{ $subsection deque }
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"Removing elements:"
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{ $subsection enque }
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{ $subsection clear-queue }
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{ $subsection queue-each }
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"An example:"
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{ $code
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"<queue> \"q\" set"
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"5 \"q\" get enque"
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"3 \"q\" get enque"
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"7 \"q\" get enque"
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"\"q\" get deque ."
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" 5"
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"\"q\" get deque ."
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" 3"
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"\"q\" get deque ."
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" 7"
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} ;
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ABOUT: "queues"
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HELP: queue
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{ $class-description "A simple first-in-first-out queue. See " { $link "queues" } "." } ;
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HELP: entry
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{ $class-description "The class of entries in a " { $link queue } ". Each entry holds an object and a reference to the next entry." } ;
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HELP: <entry>
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{ $values { "obj" object } { "entry" entry } }
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{ $description "Creates a new queue entry." }
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{ $notes "This word is a factor of " { $link enque } "." } ;
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HELP: <queue>
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{ $values { "queue" queue } }
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{ $description "Makes a new queue with no elements." } ;
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HELP: queue-empty?
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{ $values { "queue" queue } { "?" "a boolean" } }
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{ $description "Tests if a queue contains no elements." } ;
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HELP: deque
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{ $values { "queue" queue } { "elt" object } }
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{ $description "Removes an element from the front of the queue." }
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{ $errors "Throws an " { $link empty-queue-error } " if the queue has no entries." }
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{ $side-effects "queue" } ;
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HELP: enque
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{ $values { "elt" object } { "queue" queue } }
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{ $description "Adds an element to the back of the queue." }
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{ $side-effects "queue" } ;
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HELP: empty-queue-error
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{ $description "Throws an " { $link empty-queue-error } "." }
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{ $error-description "Thrown by " { $link deque } " if the queue has no entries." } ;
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HELP: clear-queue
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{ $values { "queue" queue } }
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{ $description "Removes all entries from the queue." }
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{ $side-effects "queue" } ;
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HELP: queue-each
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{ $values { "queue" queue } { "quot" "a quotation with stack effect " { $snippet "( obj -- )" } } }
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{ $description "Applies the quotation to each entry in the queue, starting from the least recently added entry, clearing the queue in the process." }
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{ $side-effects "queue" } ;
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