factor/core/collections/slicing.factor

102 lines
2.7 KiB
Factor

! Copyright (C) 2005, 2007 Slava Pestov.
! See http://factorcode.org/license.txt for BSD license.
IN: sequences-internals
USING: generic kernel math namespaces strings vectors errors
sequences ;
: (start) ( subseq seq n -- subseq seq ? )
pick length [
>r 3dup r> [ + swap nth-unsafe ] keep rot nth-unsafe =
] all? nip ; inline
: (head) 0 swap rot ; inline
: (tail) over length rot ; inline
: from-end >r dup length r> - ; inline
IN: sequences
: head-slice ( seq n -- slice ) (head) <slice> ;
: tail-slice ( seq n -- slice ) (tail) <slice> ;
: head-slice* ( seq n -- slice ) from-end head-slice ;
: tail-slice* ( seq n -- slice ) from-end tail-slice ;
: head ( seq n -- headseq ) (head) subseq ;
: tail ( seq n -- tailseq ) (tail) subseq ;
: head* ( seq n -- headseq ) from-end head ;
: tail* ( seq n -- tailseq ) from-end tail ;
: head? ( seq begin -- ? )
2dup [ length ] 2apply < [
2drop f
] [
[ length head-slice ] keep sequence=
] if ;
: ?head ( seq begin -- newseq ? )
2dup head? [ length tail t ] [ drop f ] if ;
: tail? ( seq end -- ? )
2dup [ length ] 2apply < [
2drop f
] [
[ length tail-slice* ] keep sequence=
] if ;
: ?tail ( seq end -- newseq ? )
2dup tail? [ length head* t ] [ drop f ] if ;
: replace-slice ( new m n seq -- replaced )
tuck swap tail-slice >r swap head-slice swap r> 3append ;
: remove-nth ( n seq -- newseq )
>r f swap dup 1+ r> replace-slice ;
: cut-slice ( n seq -- before after )
swap [ head ] 2keep tail-slice ;
: cut ( n seq -- before after )
swap [ head ] 2keep tail ;
: cut* ( n seq -- before after )
swap [ head* ] 2keep tail* ;
: start* ( subseq seq n -- i )
pick length pick length swap - 1+
[ (start) ] find*
swap >r 3drop r> ;
: start ( subseq seq -- i ) 0 start* ; inline
: subseq? ( subseq seq -- ? ) start -1 > ;
: split1-slice ( seq subseq -- before after )
dup pick start dup -1 = [
2drop dup like f
] [
[ >r over r> head -rot length ] keep + tail-slice
] if ;
: split1 ( seq subseq -- before after )
over >r split1-slice dup [ r> like ] [ r> drop ] if ;
: split, building get peek push ;
: split-next, V{ } clone , ;
: (split) ( quot elt -- )
swap keep swap
[ drop split-next, ] [ split, ] if ; inline
: split* ( seq quot -- pieces )
over >r
[ split-next, swap [ (split) ] each-with ]
{ } make r> swap [ swap like ] map-with ; inline
: split ( seq separators -- pieces )
swap [ over member? ] split* nip ;
: drop-prefix ( seq1 seq2 -- slice1 slice2 )
2dup mismatch dup -1 = [ drop 2dup min-length ] when
tuck tail-slice >r tail-slice r> ;
: unclip ( seq -- rest first ) dup 1 tail swap first ;