From cec0668209483a3f233574211c4b8fbd3d1d64b7 Mon Sep 17 00:00:00 2001
From: nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Mon, 1 May 2017 07:50:53 +0000
Subject: [PATCH] object.c: Kernel#yield_self

* object.c (rb_obj_yield_self): new method which yields the
  receiver and returns the result.
  [ruby-core:46320] [Feature #6721]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58528 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 NEWS                     |  4 ++++
 object.c                 | 18 ++++++++++++++++++
 test/ruby/test_object.rb |  8 ++++++++
 3 files changed, 30 insertions(+)

diff --git a/NEWS b/NEWS
index 399f1fe010..29033dd93f 100644
--- a/NEWS
+++ b/NEWS
@@ -40,6 +40,10 @@ with all sufficient information, see the ChangeLog file or Redmine
 
   * exception message "stream closed" is changed  [Bug #13405]
 
+* Kernel
+
+  * Kernel#yield_self  [Feature #6721]
+
 * Numeric
 
   * Numerical comparison operators (<,<=,>=,>) no longer rescue exceptions
diff --git a/object.c b/object.c
index 92cea14514..184a72f1fa 100644
--- a/object.c
+++ b/object.c
@@ -497,6 +497,23 @@ rb_obj_itself(VALUE obj)
     return obj;
 }
 
+/*
+ *  call-seq:
+ *     obj.yield_self {|_obj|...} -> an_object
+ *
+ *  Yields <i>obj</i> and returns the result.
+ *
+ *	'my string'.yield_self {|s|s.upcase} #=> "MY STRING"
+ *
+ */
+
+static VALUE
+rb_obj_yield_self(VALUE obj)
+{
+    RETURN_ENUMERATOR(obj, 0, 0);
+    return rb_yield_values2(1, &obj);
+}
+
 /* :nodoc: */
 VALUE
 rb_obj_init_copy(VALUE obj, VALUE orig)
@@ -3507,6 +3524,7 @@ InitVM_Object(void)
     rb_define_method(rb_mKernel, "clone", rb_obj_clone2, -1);
     rb_define_method(rb_mKernel, "dup", rb_obj_dup, 0);
     rb_define_method(rb_mKernel, "itself", rb_obj_itself, 0);
+    rb_define_method(rb_mKernel, "yield_self", rb_obj_yield_self, 0);
     rb_define_method(rb_mKernel, "initialize_copy", rb_obj_init_copy, 1);
     rb_define_method(rb_mKernel, "initialize_dup", rb_obj_init_dup_clone, 1);
     rb_define_method(rb_mKernel, "initialize_clone", rb_obj_init_dup_clone, 1);
diff --git a/test/ruby/test_object.rb b/test/ruby/test_object.rb
index d93d5594a7..6a1a82546a 100644
--- a/test/ruby/test_object.rb
+++ b/test/ruby/test_object.rb
@@ -18,6 +18,14 @@ class TestObject < Test::Unit::TestCase
     assert_same(object, object.itself, feature6373)
   end
 
+  def test_yield_self
+    feature = '[ruby-core:46320] [Feature #6721]'
+    object = Object.new
+    assert_same(self, object.yield_self {self}, feature)
+    assert_same(object, object.yield_self {|x| break x}, feature)
+    assert_instance_of(Enumerator, object.yield_self)
+  end
+
   def test_dup
     assert_equal 1, 1.dup
     assert_equal true, true.dup