From b646d1e1b83df8b417cd56794e6afc56ea29455e Mon Sep 17 00:00:00 2001
From: John Benediktsson <mrjbq7@gmail.com>
Date: Sat, 6 Apr 2013 13:06:23 -0700
Subject: [PATCH] math.combinatorics: produce type of sequence in selections.

---
 basis/math/combinatorics/combinatorics-tests.factor | 2 ++
 basis/math/combinatorics/combinatorics.factor       | 4 ++--
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/basis/math/combinatorics/combinatorics-tests.factor b/basis/math/combinatorics/combinatorics-tests.factor
index 5ae2ceffc0..89809f2d3e 100644
--- a/basis/math/combinatorics/combinatorics-tests.factor
+++ b/basis/math/combinatorics/combinatorics-tests.factor
@@ -79,6 +79,8 @@ IN: math.combinatorics.tests
     { 2 1 1 } { 2 1 2 } { 2 2 1 } { 2 2 2 } } ]
 [ { 1 2 } 3 selections ] unit-test
 
+{ { "aa" "ab" "ac" "ba" "bb" "bc" "ca" "cb" "cc" } }
+[ "abc" 2 selections ] unit-test
 
 { V{ { 1 2 } { 1 3 } } }
 [ { 1 2 3 } 2 [ { 1 } head? ] filter-combinations ] unit-test
diff --git a/basis/math/combinatorics/combinatorics.factor b/basis/math/combinatorics/combinatorics.factor
index c9109eb63d..69f2f2aca5 100644
--- a/basis/math/combinatorics/combinatorics.factor
+++ b/basis/math/combinatorics/combinatorics.factor
@@ -189,8 +189,8 @@ INSTANCE: combinations immutable-sequence
 <PRIVATE
 
 : (selections) ( seq n -- selections )
-    [ [ 1array ] map dup ] [ 1 - ] bi* [
-        cartesian-product concat [ { } concat-as ] map
+    [ dup [ 1sequence ] curry { } map-as dup ] [ 1 - ] bi* [
+        cartesian-product concat [ concat ] map
     ] with times ;
 
 PRIVATE>