[ 8 ] [ 5 6 7 8 3nip ] unit-test
[ 3 1 2 3 ] [ 1 2 3 tuckd ] unit-test
[ 1 2 3 4 ] [ 3 4 1 2 2swap ] unit-test
+
+[ 4 2 3 ] [ 1 2 3 4 shuffle( a b c d -- d b c ) ] unit-test
! Copyright (C) 2007 Chris Double, Doug Coleman.
! See http://factorcode.org/license.txt for BSD license.
-USING: kernel generalizations ;
-
+USING: accessors assocs effects.parser generalizations
+hashtables kernel locals locals.backend macros make math
+parser sequences ;
IN: shuffle
+<PRIVATE
+
+: >locals-assoc ( sequence -- assoc )
+ dup length dup 1- [ - ] curry map zip >hashtable ;
+
+PRIVATE>
+
+MACRO: shuffle-effect ( effect -- )
+ [ out>> ] [ in>> >locals-assoc ] bi
+ [
+ [ nip assoc-size , \ load-locals , ]
+ [ [ at , \ get-local , ] curry each ]
+ [ nip assoc-size , \ drop-locals , ] 2tri
+ ] [ ] make ;
+
+: shuffle(
+ ")" parse-effect parsed \ shuffle-effect parsed ; parsing
+
: 2swap ( x y z t -- z t x y ) 2 2 mnswap ; inline
: nipd ( a b c -- b c ) rot drop ; inline