Implement Enumerator::Yielder#to_proc

A Yielder object can now be directly passed to another method as a
block argument.

```ruby
enum = Enumerator.new { |y|
  Dir.glob("*.rb") { |file|
    File.open(file) { |f| f.each_line(&y) }
  }
}
```

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@67211 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 15 insertions, 0 deletions

diff --git a/test/ruby/test_enumerator.rb b/test/ruby/test_enumerator.rb
index efcfef580f..5d1e8f05b1 100644
--- a/test/ruby/test_enumerator.rb
+++ b/test/ruby/test_enumerator.rb
@@ -493,6 +493,21 @@ class TestEnumerator < Test::Unit::TestCase
     assert_equal([1, 2, 3], y.yield(2, 3))
 
     assert_raise(LocalJumpError) { Enumerator::Yielder.new }
+
+    # to_proc (explicit)
+    a = []
+    y = Enumerator::Yielder.new {|x| a << x }
+    b = y.to_proc
+    assert_kind_of(Proc, b)
+    assert_equal([1], b.call(1))
+    assert_equal([1], a)
+
+    # to_proc (implicit)
+    e = Enumerator.new { |y|
+      assert_kind_of(Enumerator::Yielder, y)
+      [1, 2, 3].each(&y)
+    }
+    assert_equal([1, 2, 3], e.to_a)
   end
 
   def test_size