* array.c (rb_ary_combination): revisit #combination behavior.

suggested by David Flanagan.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@13588 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Mon Oct  1 23:44:23 2007  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* array.c (rb_ary_combination): revisit #combination behavior.
+	  suggested by David Flanagan.
+
 Mon Oct  1 16:17:44 2007  Tanaka Akira  <akr@fsij.org>
 
 	* bootstraptest/test_method.rb: use assert_normal_exit to test

array.c

@@ -3028,13 +3028,11 @@ rb_ary_combination(VALUE ary, VALUE num)
     RETURN_ENUMERATOR(ary, 1, &num);
     n = NUM2LONG(num);
     len = RARRAY_LEN(ary);
-    if (n < 1 || len < n) {
+    if (len < n) {
 	/* yield nothing */
     }
-    else if (n == 0) {
+    else if (n <= 0) {
-	for (i = 0; i < len; i++) {
+	rb_yield(rb_ary_new2(0));
-	    rb_yield(rb_ary_new2(0));
-	}
     }
     else if (n == 1) {
 	for (i = 0; i < len; i++) {

test/ruby/test_array.rb

@@ -1178,7 +1178,7 @@ class TestArray < Test::Unit::TestCase
   end
 
 # def test_permutation
-#    assert_equal(@cls[], @cls[1,2,3].permutation(0).to_a)
+#    assert_equal(@cls[[]], @cls[1,2,3].permutation(0).to_a)
 #    assert_equal(@cls[[1],[2],[3]], @cls[1,2,3].permutation(1).to_a)
 #    assert_equal(@cls[[1,2],[1,3],[2,1],[2,3],[3,1],[3,2]], @cls[1,2,3].permutation(2).to_a)
 #    assert_equal(@cls[[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]], @cls[1,2,3].permutation(3).to_a)
@@ -1186,7 +1186,7 @@ class TestArray < Test::Unit::TestCase
 #  end
 
  def test_combination
-    assert_equal(@cls[], @cls[1,2,3,4].combination(0).to_a)
+    assert_equal(@cls[[]], @cls[1,2,3,4].combination(0).to_a)
     assert_equal(@cls[[1],[2],[3],[4]], @cls[1,2,3,4].combination(1).to_a)
     assert_equal(@cls[[1,2],[1,3],[1,4],[2,3],[2,4],[3,4]], @cls[1,2,3,4].combination(2).to_a)
     assert_equal(@cls[[1,2,3],[1,2,4],[1,3,4],[2,3,4]], @cls[1,2,3,4].combination(3).to_a)