Initial revision

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

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diff --git a/doc/forwardable.rd b/doc/forwardable.rd
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+++ b/doc/forwardable.rd
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+ -- forwardable.rb
+						
+                                                $Release Version: 1.1 $
+                                                $Revision$
+                                                $Date$
+						Original version by Tosh
+
+==begin
+
+= Forwardable
+
+A Module to define delegations for selected methods to a class.
+
+== Usage
+
+Using through extending the class.
+  
+  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)
+
+== Methods
+
+--- Forwardable#def_instance_delegators(accessor, *methods)
+
+      adding the delegations for each method of ((|methods|)) to
+      ((|accessor|)).
+
+--- Forwardable#def_instance_delegator(accessor, method, ali = method)
+      
+      adding the delegation for ((|method|)) to ((|accessor|)). When
+      you give optional argument ((|ali|)), ((|ali|)) is used as the
+      name of the delegation method, instead of ((|method|)).
+
+--- Forwardable#def_delegators(accessor, *methods)
+
+      the alias of ((|Forwardable#def_instance_delegators|)).
+
+--- Forwardable#def_delegator(accessor, method, ali = method)
+      
+      the alias of ((|Forwardable#def_instance_delegator|)).
+
+= SingleForwardable
+
+a Module to define delegations for selected methods to an object.
+
+== Usage
+
+Using through extending the object.
+
+  g = Goo.new
+  g.extend SingleForwardable
+  g.def_delegator("@out", :puts)
+  g.puts ...
+
+== Methods
+
+--- SingleForwardable#def_singleton_delegators(accessor, *methods)
+
+      adding the delegations for each method of ((|methods|)) to
+      ((|accessor|)).
+
+--- SingleForwardable#def_singleton_delegator(accessor, method, ali = method)
+
+      adding the delegation for ((|method|)) to ((|accessor|)). When
+      you give optional argument ((|ali|)), ((|ali|)) is used as the
+      name of the delegation method, instead of ((|method|)).
+
+--- SingleForwardable#def_delegators(accessor, *methods)
+
+      the alias of ((|SingleForwardable#def_instance_delegators|)).
+
+--- SingleForwardable#def_delegator(accessor, method, ali = method)
+
+      the alias of ((|SingleForwardable#def_instance_delegator|)).
+==end
\ No newline at end of file
diff --git a/doc/forwardable.rd.jp b/doc/forwardable.rd.jp
new file mode 100644
index 0000000000..a7d2ca34c7
--- /dev/null
+++ b/doc/forwardable.rd.jp
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+  -- forwatable.rb
+                                                $Release Version: 1.1 $
+                                                $Revision$
+                                                $Date$
+
+= Forwardable
+
+���饹���Ф��᥽�åɤΰѾ���ǽ��������ޤ�.
+
+== �Ȥ���
+
+���饹���Ф���extend���ƻȤ��ޤ�. 
+  
+  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)
+
+== �᥽�å�
+
+--- Forwardable#def_instance_delegators(accessor, *methods)
+
+      ((|methods|))���Ϥ��줿�᥽�åɤΥꥹ�Ȥ�((|accessor��|))�Ѿ�����
+      �褦�ˤ��ޤ�.
+
+--- Forwardable#def_instance_delegator(accessor, method, ali = method)
+
+      ((||method|))���Ϥ��줿�᥽�åɤ�((|accessor|))�˰Ѿ�����褦�ˤ�
+      �ޤ�. ((|ali|))�������Ȥ����Ϥ��줿�Ȥ���, �᥽�å�((|ali|))���Ƥ�
+      �줿�Ȥ��ˤ�, ((|accessor|))���Ф�((|method|))��ƤӽФ��ޤ�.
+
+--- Forwardable#def_delegators(accessor, *methods)
+
+      ((|Forwardable#def_instance_delegators|))����̾�Ǥ�.
+
+--- Forwardable#def_delegator(accessor, method, ali = method)
+
+      ((|Forwardable#def_instance_delegator|))����̾�Ǥ�.
+
+= SingleForwardable
+
+���֥������Ȥ��Ф�, �᥽�åɤΰѾ���ǽ��������ޤ�.
+
+== �Ȥ���
+
+���֥������Ȥ��Ф���((|extend|))���ƻȤ��ޤ�. 
+
+  g = Goo.new
+  g.extend SingleForwardable
+  g.def_delegator("@out", :puts)
+  g.puts ...
+
+== �᥽�å�
+
+--- SingleForwardable#def_singleton_delegators(accessor, *methods)
+
+      ((|methods|))���Ϥ��줿�᥽�åɤΥꥹ�Ȥ�((|accessor|))�˰Ѿ�����
+      �褦�ˤ��ޤ�.
+
+--- SingleForwardable#def_singleton_delegator(accessor, method, ali = method)
+
+      ((|method|))���Ϥ��줿�᥽�åɤ�((|accessor|))�˰Ѿ�����褦�ˤ���
+      ��. ((|ali|))�������Ȥ����Ϥ��줿�Ȥ���, �᥽�å�((|ali|))���ƤФ�
+      ���Ȥ��ˤ�, ((|accessor|))���Ф�((|method|))��ƤӽФ��ޤ�.
+
+--- SingleForwardable#def_delegators(accessor, *methods)
+
+      ((|SingleForwardable#def_singleton_delegators|))����̾�Ǥ�.
+
+--- SingleForwardable#def_delegator(accessor, method, ali = method)
+
+      ((|SingleForwardable#def_singleton_delegator|))����̾�Ǥ�.
diff --git a/lib/forwardable.rb b/lib/forwardable.rb
new file mode 100644
index 0000000000..7f57f77f53
--- /dev/null
+++ b/lib/forwardable.rb
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+#
+#   forwardable.rb - 
+#   	$Release Version: 1.1$
+#   	$Revision$
+#   	$Date$
+#   	by Keiju ISHITSUKA([email protected])
+#	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
+	  [email protected]_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
+	   [email protected]_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
+
+
+
+