backtrack: some cleanup.

db4
John Benediktsson 2015-06-01 19:46:08 -07:00
parent e2bead3328
commit 6480a46c1e
1 changed files with 15 additions and 13 deletions

View File

@ -1,8 +1,8 @@
! Copyright (C) 2008 William Schlieper
! See http://factorcode.org/license.txt for BSD license.
USING: kernel continuations combinators sequences quotations arrays namespaces
fry summary assocs math math.order macros ;
USING: assocs combinators continuations fry kernel macros math
namespaces quotations sequences summary ;
IN: backtrack
@ -13,16 +13,18 @@ ERROR: amb-failure ;
M: amb-failure summary drop "Backtracking failure" ;
: fail ( -- )
failure get [ continue ]
[ amb-failure ] if* ;
failure get [ continue ] [ amb-failure ] if* ;
: require ( ? -- )
[ fail ] unless ;
MACRO: checkpoint ( quot -- quot' )
'[ failure get _
'[ '[ failure set _ continue ] callcc0
_ failure set @ ] callcc0 ] ;
'[
failure get _ '[
'[ failure set _ continue ] callcc0
_ failure set @
] callcc0
] ;
: number-from ( from -- from+n )
[ 1 + number-from ] checkpoint ;
@ -43,10 +45,11 @@ MACRO: checkpoint ( quot -- quot' )
length 1 - 0 number-from-to nip ;
MACRO: unsafe-amb ( seq -- quot )
dup length 1 =
[ first 1quotation ]
[ [ first ] [ rest ] bi
'[ _ [ drop _ unsafe-amb ] checkpoint ] ] if ;
dup length 1 = [
first 1quotation
] [
unclip swap '[ _ [ drop _ unsafe-amb ] checkpoint ]
] if ;
PRIVATE>
@ -54,8 +57,7 @@ PRIVATE>
[ amb-integer ] [ nth ] bi ;
: amb ( seq -- elt )
[ fail f ]
[ unsafe-amb ] if-empty ; inline
[ fail f ] [ unsafe-amb ] if-empty ; inline
MACRO: amb-execute ( seq -- quot )
[ length 1 - ] [ <enum> [ 1quotation ] assoc-map ] bi