1 ! Copyright (C) 2008 Alex Chapman
2 ! See http://factorcode.org/license.txt for BSD license.
3 USING: accessors arrays kernel locals math sequences
9 GENERIC: modified-nth ( n seq -- elt )
11 M: modified nth modified-nth ;
12 M: modified nth-unsafe modified-nth ;
14 GENERIC: modified-set-nth ( elt n seq -- )
16 M: modified set-nth modified-set-nth ;
17 M: modified set-nth-unsafe modified-set-nth ;
19 INSTANCE: modified sequence
21 TUPLE: 1modified < modified seq ;
23 M: modified length seq>> length ;
24 M: modified set-length seq>> set-length ;
26 M: 1modified like seq>> like ;
27 M: 1modified new-sequence seq>> new-sequence ;
29 TUPLE: scaled < 1modified c ;
33 : scale ( seq c -- new-seq )
34 dupd <scaled> swap like ;
36 M: scaled modified-nth ( n seq -- elt )
37 [ seq>> nth ] [ c>> * ] bi ;
39 M:: scaled modified-set-nth ( elt n seq -- )
41 elt seq c>> / n seq seq>> set-nth ;
43 TUPLE: offset < 1modified n ;
47 : seq-offset ( seq n -- new-seq )
48 dupd <offset> swap like ;
50 M: offset modified-nth ( n seq -- elt )
51 [ seq>> nth ] [ n>> + ] bi ;
53 M:: offset modified-set-nth ( elt n seq -- )
54 elt seq n>> - n seq seq>> set-nth ;
56 TUPLE: summed < modified seqs ;
60 M: summed length seqs>> longest length ;
62 M: summed modified-nth ( n seq -- elt )
63 seqs>> [ ?nth [ + ] when* ] with 0 swap reduce ;
65 M: summed modified-set-nth ( elt n seq -- ) immutable ;
67 M: summed set-length ( n seq -- )
68 seqs>> [ set-length ] with each ;
70 M: summed virtual-exemplar ( summed -- seq )
73 : <2summed> ( seq seq -- summed-seq ) 2array <summed> ;
75 : <3summed> ( seq seq seq -- summed-seq ) 3array <summed> ;