1 ! Copyright (C) 2008 James Cash, Daniel Ehrenberg, Chris Double.
2 ! See http://factorcode.org/license.txt for BSD license.
3 USING: kernel sequences accessors math arrays vectors classes words
4 combinators.short-circuit combinators locals ;
9 GENERIC: car ( cons -- car )
10 GENERIC: cdr ( cons -- cdr )
11 GENERIC: nil? ( object -- ? )
13 TUPLE: cons { car read-only } { cdr read-only } ;
17 M: cons car ( cons -- car ) car>> ;
19 M: cons cdr ( cons -- cdr ) cdr>> ;
22 M: +nil+ nil? drop t ;
23 M: object nil? drop f ;
25 : atom? ( obj -- ? ) list? not ; inline
27 : nil ( -- symbol ) +nil+ ; inline
29 : uncons ( cons -- car cdr ) [ car ] [ cdr ] bi ; inline
31 : swons ( cdr car -- cons ) swap cons ; inline
33 : unswons ( cons -- cdr car ) uncons swap ; inline
35 : 1list ( obj -- cons ) nil cons ; inline
37 : 1list? ( list -- ? ) { [ nil? not ] [ cdr nil? ] } 1&& ; inline
39 : 2list ( a b -- cons ) nil cons cons ; inline
41 : 3list ( a b c -- cons ) nil cons cons cons ; inline
43 : cadr ( list -- elt ) cdr car ; inline
45 : 2car ( list -- car caar ) [ car ] [ cdr car ] bi ; inline
47 : 3car ( list -- car cadr caddr ) [ car ] [ cdr car ] [ cdr cdr car ] tri ; inline
49 : lnth ( n list -- elt ) swap [ cdr ] times car ; inline
53 : (leach) ( list quot -- cdr quot )
54 [ [ car ] dip call ] [ [ cdr ] dip ] 2bi ; inline
58 : leach ( list quot: ( elt -- ) -- )
59 over nil? [ 2drop ] [ (leach) leach ] if ; inline recursive
61 : lmap ( list quot: ( elt -- ) -- result )
62 over nil? [ drop ] [ (leach) lmap cons ] if ; inline recursive
64 : foldl ( list identity quot: ( obj1 obj2 -- obj ) -- result )
67 :: foldr ( list identity quot: ( obj1 obj2 -- obj ) -- result )
68 list nil? [ identity ] [
69 list cdr identity quot foldr
71 ] if ; inline recursive
73 : llength ( list -- n )
74 0 [ drop 1 + ] foldl ;
76 : lreverse ( list -- newlist )
77 nil [ swap cons ] foldl ;
79 : lappend ( list1 list2 -- newlist )
80 [ lreverse ] dip [ swap cons ] foldl ;
82 : lcut ( list index -- before after )
84 [ [ unswons ] dip cons ] times
87 : sequence>list ( sequence -- list )
88 <reversed> nil [ swons ] reduce ;
90 : lmap>array ( list quot -- array )
91 accumulator [ leach ] dip { } like ; inline
93 : list>array ( list -- array )
96 :: traverse ( list pred quot: ( list/elt -- result ) -- result )
98 elt dup pred call [ quot call ] when
99 dup list? [ pred quot traverse ] when
100 ] lmap ; inline recursive