64 lines
2.3 KiB
Factor
64 lines
2.3 KiB
Factor
|
!:folding=indent:collapseFolds=1:
|
||
|
|
||
|
! $Id$
|
||
|
!
|
||
|
! Copyright (C) 2004 Slava Pestov.
|
||
|
!
|
||
|
! Redistribution and use in source and binary forms, with or without
|
||
|
! modification, are permitted provided that the following conditions are met:
|
||
|
!
|
||
|
! 1. Redistributions of source code must retain the above copyright notice,
|
||
|
! this list of conditions and the following disclaimer.
|
||
|
!
|
||
|
! 2. Redistributions in binary form must reproduce the above copyright notice,
|
||
|
! this list of conditions and the following disclaimer in the documentation
|
||
|
! and/or other materials provided with the distribution.
|
||
|
!
|
||
|
! THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
|
||
|
! INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
|
||
|
! FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
|
||
|
! DEVELOPERS AND CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
||
|
! SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
|
||
|
! PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
|
||
|
! OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
|
||
|
! WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
|
||
|
! OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
|
||
|
! ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
||
|
|
||
|
IN: lists
|
||
|
USE: logic
|
||
|
USE: combinators
|
||
|
USE: kernel
|
||
|
USE: stack
|
||
|
|
||
|
: assoc? ( list -- ? )
|
||
|
#! Push if the list appears to be an alist (each element is
|
||
|
#! a cons).
|
||
|
dup list? [ [ cons? ] all? ] [ drop f ] ifte ;
|
||
|
|
||
|
: assoc* ( key alist -- [ key | value ] )
|
||
|
#! Looks up the key in an alist. Push the key/value pair.
|
||
|
#! Most of the time you want to use assoc not assoc*.
|
||
|
dup [
|
||
|
2dup car car = [
|
||
|
nip car
|
||
|
] [
|
||
|
cdr assoc*
|
||
|
] ifte
|
||
|
] [
|
||
|
2drop f
|
||
|
] ifte ;
|
||
|
|
||
|
: assoc ( key alist -- value )
|
||
|
#! Looks up the key in an alist. An alist is a proper list
|
||
|
#! of comma pairs, the car of each pair is a key, the cdr is
|
||
|
#! the value. For example:
|
||
|
#! [ [ 1 | "one" ] [ 2 | "two" ] [ 3 | "three" ] ]
|
||
|
assoc* dup [ cdr ] when ;
|
||
|
|
||
|
: set-assoc ( value key alist -- alist )
|
||
|
#! Sets the key in the alist. Does not modify the existing
|
||
|
#! list by consing a new key/value pair onto the alist. The
|
||
|
#! newly-added pair 'shadows' the previous value.
|
||
|
>r swons r> [ dupd car= not ] subset cons ;
|