5 files changed, 41 insertions, 8 deletions
diff --git a/mrbgems/mruby-object-ext/mrbgem.rake b/mrbgems/mruby-object-ext/mrbgem.rake
index 980f1667a..91a6e7ff1 100644
--- a/mrbgems/mruby-object-ext/mrbgem.rake
+++ b/mrbgems/mruby-object-ext/mrbgem.rake
@@ -1,4 +1,5 @@
 MRuby::Gem::Specification.new('mruby-object-ext') do |spec|
   spec.license = 'MIT'
   spec.author  = 'mruby developers'
+  spec.summary = 'extensional Object class'
 end
diff --git a/mrbgems/mruby-object-ext/mrblib/object.rb b/mrbgems/mruby-object-ext/mrblib/object.rb
new file mode 100644
index 000000000..581156cb0
--- /dev/null
+++ b/mrbgems/mruby-object-ext/mrblib/object.rb
@@ -0,0 +1,19 @@
+class Object
+  ##
+  #  call-seq:
+  #     obj.tap{|x|...}    -> obj
+  #
+  #  Yields <code>x</code> to the block, and then returns <code>x</code>.
+  #  The primary purpose of this method is to "tap into" a method chain,
+  #  in order to perform operations on intermediate results within the chain.
+  #
+  #  (1..10)                .tap {|x| puts "original: #{x.inspect}"}
+  #    .to_a                .tap {|x| puts "array: #{x.inspect}"}
+  #    .select {|x| x%2==0} .tap {|x| puts "evens: #{x.inspect}"}
+  #    .map { |x| x*x }     .tap {|x| puts "squares: #{x.inspect}"}
+  #
+  def tap
+    yield self
+    self
+  end
+end
diff --git a/mrbgems/mruby-object-ext/src/object.c b/mrbgems/mruby-object-ext/src/object.c
index 927a23d66..2bc9cbf4f 100644
--- a/mrbgems/mruby-object-ext/src/object.c
+++ b/mrbgems/mruby-object-ext/src/object.c
@@ -59,9 +59,6 @@ nil_to_i(mrb_state *mrb, mrb_value obj)
  *     k.instance_exec(5) {|x| @secret+x }   #=> 104
  */
 
-mrb_value
-mrb_yield_internal(mrb_state *mrb, mrb_value b, int argc, mrb_value *argv, mrb_value self, struct RClass *c);
-
 static mrb_value
 mrb_obj_instance_exec(mrb_state *mrb, mrb_value self)
 {
@@ -87,7 +84,7 @@ mrb_obj_instance_exec(mrb_state *mrb, mrb_value self)
     break;
   }
 
-  return mrb_yield_internal(mrb, blk, argc, argv, self, c);
+  return mrb_yield_with_class(mrb, blk, argc, argv, self, c);
 }
 
 void
diff --git a/mrbgems/mruby-object-ext/test/nil.rb b/mrbgems/mruby-object-ext/test/nil.rb
index e385dec6a..5cd1cf4ed 100644
--- a/mrbgems/mruby-object-ext/test/nil.rb
+++ b/mrbgems/mruby-object-ext/test/nil.rb
@@ -1,11 +1,11 @@
 assert('NilClass#to_a') do
-  assert_equal nil.to_a, []
+  assert_equal [], nil.to_a
 end
 
 assert('NilClass#to_f') do
-  assert_equal nil.to_f, 0.0
+  assert_equal 0.0, nil.to_f
 end
 
 assert('NilClass#to_i') do
-  assert_equal nil.to_i, 0
+  assert_equal 0, nil.to_i
 end
diff --git a/mrbgems/mruby-object-ext/test/object.rb b/mrbgems/mruby-object-ext/test/object.rb
index 1a75622f6..fe56f1ec5 100644
--- a/mrbgems/mruby-object-ext/test/object.rb
+++ b/mrbgems/mruby-object-ext/test/object.rb
@@ -5,5 +5,21 @@ assert('Object#instance_exec') do
     end
   end
   k = KlassWithSecret.new
-  assert_equal k.instance_exec(5) {|x| @secret+x }, 104
+  assert_equal 104, k.instance_exec(5) {|x| @secret+x }
+end
+
+assert('Object#tap') do
+  ret = []
+  (1..10)                 .tap {|x| ret << "original: #{x.inspect}"}
+     .to_a                .tap {|x| ret << "array: #{x.inspect}"}
+     .select {|x| x%2==0} .tap {|x| ret << "evens: #{x.inspect}"}
+     .map { |x| x*x }     .tap {|x| ret << "squares: #{x.inspect}"}
+
+  assert_equal [
+    "original: 1..10",
+    "array: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]",
+    "evens: [2, 4, 6, 8, 10]",
+    "squares: [4, 16, 36, 64, 100]"
+  ], ret
+  assert_equal(:tap_ok, Class.new {def m; tap{return :tap_ok}; end}.new.m)
 end