Implement Array#minmax

Array#minmax was previous not implemented, so calling #minmax on
array was actually calling Enumerable#minmax.  This is a simple
implementation of #minmax by just calling rb_ary_min and
rb_ary_max, which improves performance significantly.

Fixes [Bug #15929]

1 files changed, 19 insertions, 0 deletions

diff --git a/test/ruby/test_array.rb b/test/ruby/test_array.rb
index 6cb96ebe7a..c6aff553ff 100644
--- a/test/ruby/test_array.rb
+++ b/test/ruby/test_array.rb
@@ -1792,6 +1792,25 @@ class TestArray < Test::Unit::TestCase
     assert_same(obj, [obj, 1.0].max)
   end
 
+  def test_minmax
+    assert_equal([1, 3], [1, 2, 3, 1, 2].minmax)
+    assert_equal([3, 1], [1, 2, 3, 1, 2].minmax {|a,b| b <=> a })
+    cond = ->((a, ia), (b, ib)) { (b <=> a).nonzero? or ia <=> ib }
+    assert_equal([[3, 2], [1, 3]], [1, 2, 3, 1, 2].each_with_index.minmax(&cond))
+    ary = %w(albatross dog horse)
+    assert_equal(["albatross", "horse"], ary.minmax)
+    assert_equal(["dog", "albatross"], ary.minmax {|a,b| a.length <=> b.length })
+    assert_equal([1, 3], [3,2,1].minmax)
+
+    class << (obj = Object.new)
+      def <=>(x) 1 <=> x end
+      def coerce(x) [x, 1] end
+    end
+    ary = [obj, 1.0].minmax
+    assert_same(obj, ary[0])
+    assert_equal(obj, ary[1])
+  end
+
   def test_uniq
     a = []
     b = a.uniq