20 lines
450 B
Factor
20 lines
450 B
Factor
! Copyright (C) 2008 Slava Pestov.
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! See http://factorcode.org/license.txt for BSD license.
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USING: sequences kernel ;
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IN: persistent.sequences
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GENERIC: ppush ( val seq -- seq' )
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M: sequence ppush swap suffix ;
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GENERIC: ppop ( seq -- seq' )
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M: sequence ppop 1 head* ;
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GENERIC: new-nth ( val i seq -- seq' )
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M: sequence new-nth clone [ set-nth ] keep ;
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: changed-nth ( i seq quot -- seq' )
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[ [ nth ] dip call ] [ drop new-nth ] 3bi ; inline
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