From decd9ed1eec38f0a91ccd3f08d5ae70e19a8af06 Mon Sep 17 00:00:00 2001
From: John Benediktsson <mrjbq7@gmail.com>
Date: Sat, 6 Apr 2013 13:12:57 -0700
Subject: [PATCH] math.combinatorics: make permutations-quot to reduce code
 duplication.

---
 basis/math/combinatorics/combinatorics.factor | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/basis/math/combinatorics/combinatorics.factor b/basis/math/combinatorics/combinatorics.factor
index 69f2f2aca5..490d496992 100644
--- a/basis/math/combinatorics/combinatorics.factor
+++ b/basis/math/combinatorics/combinatorics.factor
@@ -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