factor/basis/lists/lists.factor

138 lines
3.3 KiB
Factor

! Copyright (C) 2008 James Cash, Daniel Ehrenberg, Chris Double.
! See http://factorcode.org/license.txt for BSD license.
USING: accessors combinators combinators.short-circuit kernel
lexer locals make math namespaces parser sequences words ;
IN: lists
! List Protocol
MIXIN: list
GENERIC: car ( cons -- car )
GENERIC: cdr ( cons -- cdr )
GENERIC: nil? ( object -- ? )
TUPLE: cons-state { car read-only } { cdr read-only } ;
C: cons cons-state
M: cons-state car car>> ;
M: cons-state cdr cdr>> ;
SINGLETON: +nil+
M: +nil+ nil? drop t ;
M: object nil? drop f ;
: atom? ( obj -- ? ) list? not ; inline
: nil ( -- symbol ) +nil+ ; inline
: uncons ( cons -- car cdr ) [ car ] [ cdr ] bi ; inline
: swons ( cdr car -- cons ) swap cons ; inline
: unswons ( cons -- cdr car ) uncons swap ; inline
: 1list ( obj -- cons ) nil cons ; inline
: 1list? ( list -- ? ) { [ nil? not ] [ cdr nil? ] } 1&& ; inline
: 2list ( a b -- cons ) 1list cons ; inline
: 3list ( a b c -- cons ) 2list cons ; inline
: cadr ( list -- elt ) cdr car ; inline
: 2car ( list -- car cadr ) uncons car ; inline
: 3car ( list -- car cadr caddr ) uncons uncons car ; inline
: lnth ( n list -- elt ) swap [ cdr ] times car ; inline
<PRIVATE
: (leach) ( list quot -- cdr quot )
[ [ car ] dip call ] [ [ cdr ] dip ] 2bi ; inline
PRIVATE>
: leach ( ... list quot: ( ... elt -- ... ) -- ... )
over nil? [ 2drop ] [ (leach) leach ] if ; inline recursive
: foldl ( ... list identity quot: ( ... prev elt -- ... next ) -- ... result )
swapd leach ; inline
:: foldr ( ... list identity quot: ( ... prev elt -- ... next ) -- ... result )
list nil? [
identity
] [
list cdr identity quot foldr
list car quot call
] if ; inline recursive
: llength ( list -- n )
0 [ drop 1 + ] foldl ;
: lreverse ( list -- newlist )
nil [ swons ] foldl ;
: lmap ( ... list quot: ( ... elt -- ... newelt ) -- ... result )
[ nil ] dip [ swapd dip cons ] curry foldl lreverse ; inline
: lappend ( list1 list2 -- newlist )
[ lreverse ] dip [ swons ] foldl ;
: lcut ( list index -- before after )
[ nil ] dip [ [ unswons ] dip cons ] times lreverse swap ;
: sequence>list ( sequence -- list )
<reversed> nil [ swons ] reduce ;
: lmap>array ( ... list quot: ( ... elt -- ... newelt ) -- ... array )
collector [ leach ] dip { } like ; inline
: list>array ( list -- array )
[ ] lmap>array ;
: deeplist>array ( list -- array )
[ dup list? [ deeplist>array ] when ] lmap>array ;
INSTANCE: cons-state list
INSTANCE: +nil+ list
GENERIC: >list ( object -- list )
M: list >list ;
M: sequence >list sequence>list ;
ERROR: list-syntax-error ;
<PRIVATE
: items>list ( sequence -- list )
[ +nil+ ] [
<reversed> unclip-slice [ swons ] reduce
] if-empty ;
: ?list-syntax-error ( right-of-dot? -- )
building get empty? or [ list-syntax-error ] when ;
: (parse-list-literal) ( right-of-dot? -- )
scan-token {
{ "}" [ drop +nil+ , ] }
{ "." [ ?list-syntax-error t (parse-list-literal) ] }
[
parse-datum dup parsing-word? [
V{ } clone swap execute-parsing first
] when
, [ "}" expect ] [ f (parse-list-literal) ] if
]
} case ;
: parse-list-literal ( -- list )
[ f (parse-list-literal) ] { } make items>list ;
PRIVATE>
SYNTAX: L{ parse-list-literal suffix! ;