21 lines
534 B
Factor
21 lines
534 B
Factor
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USING: kernel sequences sequences.private math ;
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IN: sequences.next
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<PRIVATE
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: (map-next) ( i seq quot -- )
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! this uses O(n) more bounds checks than is really necessary
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>r [ >r 1+ r> ?nth ] 2keep nth-unsafe r> call ; inline
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PRIVATE>
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: each-next ( seq quot -- )
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! quot: next-elt elt --
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iterate-seq [ (map-next) ] 2curry each-integer ; inline
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: map-next ( seq quot -- newseq )
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! quot: next-elt elt -- newelt
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over dup length swap new >r
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iterate-seq [ (map-next) ] 2curry
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r> [ collect ] keep ; inline
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