Method reference operator

Introduce the new operator for method reference, `.:`.
[Feature #12125] [Feature #13581]
[EXPERIMENTAL]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66667 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

5 files changed, 38 insertions, 0 deletions

diff --git a/test/ripper/test_parser_events.rb b/test/ripper/test_parser_events.rb
index 95ec661fcf..3c78daf16e 100644
--- a/test/ripper/test_parser_events.rb
+++ b/test/ripper/test_parser_events.rb
@@ -434,6 +434,13 @@ class TestRipper::ParserEvents < Test::Unit::TestCase
     assert_equal "[call(ref(self),&.,foo,[])]", tree
   end
 
+  def test_methref
+    thru_methref = false
+    tree = parse("obj.:foo", :on_methref) {thru_methref = true}
+    assert_equal true, thru_methref
+    assert_equal "[methref(vcall(obj),foo)]", tree
+  end
+
   def test_excessed_comma
     thru_excessed_comma = false
     parse("proc{|x,|}", :on_excessed_comma) {thru_excessed_comma = true}
diff --git a/test/ripper/test_scanner_events.rb b/test/ripper/test_scanner_events.rb
index c9fce34a77..94df6616e8 100644
--- a/test/ripper/test_scanner_events.rb
+++ b/test/ripper/test_scanner_events.rb
@@ -550,6 +550,8 @@ class TestRipper::ScannerEvents < Test::Unit::TestCase
                  scan('op', ':[]=')
     assert_equal ['&.'],
                  scan('op', 'a&.f')
+    assert_equal %w(.:),
+                 scan('op', 'obj.:foo')
     assert_equal [],
                  scan('op', %q[`make all`])
   end
diff --git a/test/ruby/test_ast.rb b/test/ruby/test_ast.rb
index 055567d574..ed4bcb37c0 100644
--- a/test/ruby/test_ast.rb
+++ b/test/ruby/test_ast.rb
@@ -249,4 +249,13 @@ class TestAst < Test::Unit::TestCase
     assert_equal(:b, mid)
     assert_equal(:SCOPE, defn.type)
   end
+
+  def test_methref
+    node = RubyVM::AbstractSyntaxTree.parse("obj.:foo")
+    _, _, body = *node.children
+    assert_equal(:METHREF, body.type)
+    recv, mid = body.children
+    assert_equal(:VCALL, recv.type)
+    assert_equal(:foo, mid)
+  end
 end
diff --git a/test/ruby/test_method.rb b/test/ruby/test_method.rb
index a9051b81fa..5cfcdb8dc5 100644
--- a/test/ruby/test_method.rb
+++ b/test/ruby/test_method.rb
@@ -1095,4 +1095,23 @@ class TestMethod < Test::Unit::TestCase
       (f >> 5).call(2)
     }
   end
+
+  def test_method_reference_operator
+    m = 1.:succ
+    assert_equal(1.method(:succ), m)
+    assert_equal(2, m.())
+    m = 1.:+
+    assert_equal(1.method(:+), m)
+    assert_equal(42, m.(41))
+    m = 1.:-@
+    assert_equal(1.method(:-@), m)
+    assert_equal(-1, m.())
+    o = Object.new
+    def o.foo; 42; end
+    m = o.method(:foo)
+    assert_equal(m, o.:foo)
+    def o.method(m); nil; end
+    assert_equal(m, o.:foo)
+    assert_nil(o.method(:foo))
+  end
 end
diff --git a/test/ruby/test_syntax.rb b/test/ruby/test_syntax.rb
index dee9187a9c..5534056327 100644
--- a/test/ruby/test_syntax.rb
+++ b/test/ruby/test_syntax.rb
@@ -908,6 +908,7 @@ eom
   def test_fluent_dot
     assert_valid_syntax("a\n.foo")
     assert_valid_syntax("a\n&.foo")
+    assert_valid_syntax("a\n.:foo")
   end
 
   def test_no_warning_logop_literal