Merge pull request #1923 from ksss/hash-enumerator-select

Hash#{select,select!} support return Enumerator

mrbgems/mruby-enumerator/test/enumerator.rb

@@ -494,6 +494,20 @@ assert 'Hash#each_value' do
   assert_equal [1,2], {a:1,b:2}.each_value.to_a.sort
 end
 
+assert 'Hash#select' do
+  h = {1=>2,3=>4,5=>6}
+  hret = h.select.with_index {|a,b| a[1] == 4}
+  assert_equal({3=>4}, hret)
+  assert_equal({1=>2,3=>4,5=>6}, h)
+end
+
+assert 'Hash#select!' do
+  h = {1=>2,3=>4,5=>6}
+  hret = h.select!.with_index {|a,b| a[1] == 4}
+  assert_equal h, hret
+  assert_equal({3=>4}, h)
+end
+
 assert 'Range#each' do
   a = (1..5)
   b = a.each

mrblib/hash.rb

@@ -162,10 +162,12 @@ class Hash
 
   # 1.9 Hash#select! returns Hash; ISO says nothing.
   def select!(&b)
+    return to_enum :select! unless block_given?
+
     keys = []
     self.each_key{|k|
       v = self[k]
-      unless b.call(k, v)
+      unless b.call([k, v])
         keys.push(k)
       end
     }
@@ -178,10 +180,12 @@ class Hash
 
   # 1.9 Hash#select returns Hash; ISO says nothing.
   def select(&b)
+    return to_enum :select unless block_given?
+
     h = {}
     self.each_key{|k|
       v = self[k]
-      if b.call(k, v)
+      if b.call([k, v])
         h[k] = v
       end
     }