[GR-20075] Implement Method#<< and Method#>> (#1821).

PullRequest: truffleruby/1182

Author: bjfish

CHANGELOG.md

@@ -52,6 +52,7 @@ Compatibility:
 * Implemented `rb_hash_start` (#1841, @XrXr).
 * JCodings has been updated from 1.0.42 to 1.0.45.
 * Joni has been updated from 2.1.25 to 2.1.30.
+* Implemented `Method#<<` and `Method#>>` (#1821).
 
 Performance:
 

spec/ruby/core/proc/compose_spec.rb

@@ -38,6 +38,22 @@ def double.call(n); n * 2; end
         (f << g).lambda?.should == false
       end
 
+      it "is a Proc when other is lambda" do
+        f = proc { |x| x * x }
+        g = ->(x) { x + x }
+
+        (f << g).is_a?(Proc).should == true
+        (f << g).lambda?.should == false
+      end
+
+      it "is a lambda when self is lambda" do
+        f = lambda { |x| x * x }
+        g = proc { |x| x + x }
+
+        (f << g).is_a?(Proc).should == true
+        (f << g).lambda?.should == true
+      end
+
       it "may accept multiple arguments" do
         inc = proc { |n| n + 1 }
         mul = proc { |n, m| n * m }
@@ -91,6 +107,22 @@ def double.call(n); n * 2; end
         (f >> g).lambda?.should == false
       end
 
+      it "is a Proc when other is lambda" do
+        f = proc { |x| x * x }
+        g = ->(x) { x + x }
+
+        (f >> g).is_a?(Proc).should == true
+        (f >> g).lambda?.should == false
+      end
+
+      it "is a lambda when self is lambda" do
+        f = lambda { |x| x * x }
+        g = proc { |x| x + x }
+
+        (f >> g).is_a?(Proc).should == true
+        (f >> g).lambda?.should == true
+      end
+
       it "may accept multiple arguments" do
         inc = proc { |n| n + 1 }
         mul = proc { |n, m| n * m }

spec/tags/core/method/compose_tags.txt

@@ -30,6 +30,14 @@ def curry(curried_arity = nil)
     self.to_proc.curry(curried_arity)
   end
 
+  def >>(other)
+    self.to_proc >> other
+  end
+
+  def <<(other)
+    self.to_proc << other
+  end
+
   alias_method :to_s, :inspect
 
 end

src/main/ruby/truffleruby/core/method.rb

@@ -105,7 +105,7 @@ def to_proc
   end
 
   def >>(other)
-    if other.respond_to?(:lambda?) && other.lambda?
+    if lambda?
       -> (*args, &block) do
         other.call(call(*args, &block))
       end
@@ -117,7 +117,7 @@ def >>(other)
   end
 
   def <<(other)
-    if other.respond_to?(:lambda?) && other.lambda?
+    if lambda?
       -> (*args, &block) do
         call(other.call(*args, &block))
       end