34 lines
725 B
Factor
34 lines
725 B
Factor
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! Copyright (C) 2006 Chris Double.
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! See http://factorcode.org/license.txt for BSD license.
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USING: kernel lazy-lists io ;
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IN: lazy-lists
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TUPLE: lazy-contents stream car cdr ;
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: lcontents ( stream -- result )
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f f <lazy-contents> ;
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M: lazy-contents car ( lazy-contents -- car )
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dup lazy-contents-car dup [
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nip
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] [
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drop dup lazy-contents-stream stream-read1
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swap dupd set-lazy-contents-car
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] if ;
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M: lazy-contents cdr ( lazy-contents -- cdr )
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dup lazy-contents-cdr dup [
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nip
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] [
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drop dup
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[ lazy-contents-stream ] keep
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car [
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lcontents [ swap set-lazy-contents-cdr ] keep
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] [
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2drop nil
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] if
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] if ;
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M: lazy-contents nil? ( lazy-contents -- bool )
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car not ;
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