Hash#each_{key,value} support return Enumerator

if non block given

mrbgems/mruby-enumerator/test/enumerator.rb

@@ -486,6 +486,14 @@ assert 'Hash#each' do
   assert_equal [[:a,1], [:b,2]], c.sort
 end
 
+assert 'Hash#each_key' do
+  assert_equal [:a,:b], {a:1,b:2}.each_key.to_a.sort
+end
+
+assert 'Hash#each_value' do
+  assert_equal [1,2], {a:1,b:2}.each_value.to_a.sort
+end
+
 assert 'Range#each' do
   a = (1..5)
   b = a.each

mrblib/hash.rb

@@ -69,6 +69,8 @@ class Hash
   #
   # ISO 15.2.13.4.10
   def each_key(&block)
+    return to_enum :each_key unless block_given?
+
     self.keys.each{|k| block.call(k)}
     self
   end
@@ -93,6 +95,8 @@ class Hash
   #
   # ISO 15.2.13.4.11
   def each_value(&block)
+    return to_enum :each_value unless block_given?
+
     self.keys.each{|k| block.call(self[k])}
     self
   end