22 lines
618 B
Factor
22 lines
618 B
Factor
USING: kernel sequences sequences.private math ;
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IN: sequences.next
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<PRIVATE
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: iterate-seq ( seq quot -- i seq quot )
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[ [ length ] keep ] dip ; inline
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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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[ [ [ 1+ ] dip ?nth ] 2keep nth-unsafe ] dip call ; inline
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PRIVATE>
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: each-next ( seq quot: ( next-elt elt -- ) -- )
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iterate-seq [ (map-next) ] 2curry each-integer ; inline
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: map-next ( seq quot: ( next-elt elt -- newelt ) -- newseq )
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over dup length swap new-sequence [
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iterate-seq [ (map-next) ] 2curry
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] dip [ collect ] keep ; inline
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