Initial revision

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@1375 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/forwardable.rb

@@ -0,0 +1,94 @@
+#
+#   forwardable.rb - 
+#   	$Release Version: 1.1$
+#   	$Revision$
+#   	$Date$
+#   	by Keiju ISHITSUKA(keiju@ishitsuka.com)
+#	original definition by delegator.rb
+# --
+# Usage:
+#
+#   class Foo
+#     extend Forwardable
+#
+#     def_delegators("@out", "printf", "print")
+#     def_delegators(:@in, :gets)
+#     def_delegator(:@contents, :[], "content_at")
+#   end
+#   f = Foo.new
+#   f.printf ...
+#   f.gets
+#   f.content_at(1)
+#
+#   g = Goo.new
+#   g.extend SingleForwardable
+#   g.def_delegator("@out", :puts)
+#   g.puts ...
+#
+#
+
+module Forwardable
+
+  @debug = nil
+  class<<self
+    attr_accessor :debug
+  end
+
+  def def_instance_delegators(accessor, *methods)
+    for method in methods
+      def_instance_delegator(accessor, method)
+    end
+  end
+
+  def def_instance_delegator(accessor, method, ali = method)
+    accessor = accessor.id2name if accessor.kind_of?(Integer)
+    method = method.id2name if method.kind_of?(Integer)
+    ali = ali.id2name if ali.kind_of?(Integer)
+
+    module_eval(<<-EOS, "(__FORWARDABLE__)", 1)
+      def #{ali}(*args, &block)
+	begin
+	  #{accessor}.__send__(:#{method}, *args, &block)
+	rescue Exception
+	  $@.delete_if{|s| /^\\(__FORWARDABLE__\\):/ =~ s} unless Forwardable::debug
+	  raise
+	end
+      end
+    EOS
+  end
+
+  alias def_delegators def_instance_delegators
+  alias def_delegator def_instance_delegator
+end
+
+module SingleForwardable
+  def def_singleton_delegators(accessor, *methods)
+    for method in methods
+      def_singleton_delegator(accessor, method)
+    end
+  end
+
+  def def_singleton_delegator(accessor, method, ali = method)
+    accessor = accessor.id2name if accessor.kind_of?(Integer)
+    method = method.id2name if method.kind_of?(Integer)
+    ali = ali.id2name if ali.kind_of?(Integer)
+
+    instance_eval(<<-EOS, "(__FORWARDABLE__)", 1)
+       def #{ali}(*args, &block)
+	 begin
+	   #{accessor}.__send__(:#{method}, *args,&block)
+	 rescue Exception
+	   $@.delete_if{|s| /^\\(__FORWARDABLE__\\):/ =~ s} unless Forwardable::debug
+	   raise
+	 end
+       end
+    EOS
+  end
+
+  alias def_delegators def_singleton_delegators
+  alias def_delegator def_singleton_delegator
+end
+
+
+
+