1 ! Copyright (C) 2008 Slava Pestov.
2 ! See http://factorcode.org/license.txt for BSD license.
3 USING: sequences kernel ;
4 IN: persistent.sequences
6 GENERIC: ppush ( val seq -- seq' )
8 M: sequence ppush swap suffix ;
10 GENERIC: ppop ( seq -- seq' )
12 M: sequence ppop 1 head* ;
14 GENERIC: new-nth ( val i seq -- seq' )
16 M: sequence new-nth clone [ set-nth ] keep ;
18 : changed-nth ( i seq quot -- seq' )
19 [ [ nth ] dip call ] [ drop new-nth ] 3bi ; inline