factor/library/collections/virtual-sequences.factor

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1.9 KiB
Factor

! Copyright (C) 2005, 2006 Slava Pestov.
! See http://factorcode.org/license.txt for BSD license.
IN: sequences
USING: errors generic kernel math sequences-internals vectors ;
! A reversal of an underlying sequence.
TUPLE: reversed seq ;
: reversed@ ( m reversed -- n seq )
reversed-seq [ length swap - 1- ] keep ; inline
M: reversed length reversed-seq length ;
M: reversed nth reversed@ nth ;
M: reversed nth-unsafe reversed@ nth-unsafe ;
M: reversed set-nth reversed@ set-nth ;
M: reversed set-nth-unsafe
reversed@ set-nth-unsafe ;
M: reversed like reversed-seq like ;
M: reversed thaw reversed-seq thaw ;
: reverse ( seq -- newseq ) [ <reversed> ] keep like ;
! A slice of another sequence.
TUPLE: slice seq from to ;
: collapse-slice ( from to slice -- from to seq )
dup slice-from swap slice-seq >r tuck + >r + r> r> ;
TUPLE: slice-error reason ;
: slice-error ( str -- * ) <slice-error> throw ;
: check-slice ( from to seq -- )
pick 0 < [ "start < 0" slice-error ] when
length over < [ "end > sequence" slice-error ] when
> [ "start > end" slice-error ] when ;
C: slice ( m n seq -- slice )
#! A slice of a slice collapses.
>r dup slice? [ collapse-slice ] when r>
>r 3dup check-slice r>
[ set-slice-seq ] keep
[ set-slice-to ] keep
[ set-slice-from ] keep ;
M: slice length
dup slice-to swap slice-from - ;
: slice@ ( m slice -- n seq )
[ slice-from + ] keep slice-seq ; inline
M: slice nth slice@ nth ;
M: slice nth-unsafe slice@ nth-unsafe ;
M: slice set-nth slice@ set-nth ;
M: slice set-nth-unsafe slice@ set-nth-unsafe ;
M: slice like slice-seq like ;
M: slice thaw slice-seq thaw ;
TUPLE: column seq col ;
: column@ ( m column -- n seq )
dup column-col -rot column-seq nth ;
M: column length column-seq length ;
M: column nth column@ nth ;
M: column set-nth column@ set-nth ;
M: column like column-seq like ;
M: column thaw column-seq thaw ;