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math.combinatorics: make permutations-quot to reduce code duplication.

db4
John Benediktsson 2013-04-06 13:12:57 -07:00
parent b646d1e1b8
commit decd9ed1ee
1 changed files with 11 additions and 7 deletions
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18
basis/math/combinatorics/combinatorics.factor
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@ -68,13 +68,18 @@ M: permutations hashcode* tuple-hashcode ;
INSTANCE: permutations immutable-sequence
<PRIVATE
: permutations-quot ( seq quot -- seq quot' )
[ [ permutation-iota ] keep ] dip '[ _ permutation @ ] ; inline
PRIVATE>
: each-permutation ( seq quot -- )
[ [ permutation-iota ] keep ] dip
'[ _ permutation @ ] each ; inline
permutations-quot each ; inline
: map-permutations ( seq quot -- seq' )
[ [ permutation-iota ] keep ] dip
'[ _ permutation @ ] map ; inline
permutations-quot map ; inline
: filter-permutations ( seq quot -- seq' )
selector [ each-permutation ] dip ; inline
@ -83,9 +88,8 @@ INSTANCE: permutations immutable-sequence
[ ] map-permutations ;
: find-permutation ( seq quot -- elt )
[ dup [ permutation-iota ] keep ] dip
'[ _ permutation @ ] find drop
[ swap permutation ] [ drop f ] if* ; inline
[ permutations-quot find drop ]
[ drop over [ permutation ] [ 2drop f ] if ] 2bi ; inline
: reduce-permutations ( seq identity quot -- result )
swapd each-permutation ; inline