merges r20385 from trunk into ruby_1_9_1.

--
 * lib/foerwardable.rb: should be usable def_single_delegator for
   Class and Module.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_1@24174 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

3 files changed, 118 insertions, 19 deletions

diff --git a/ChangeLog b/ChangeLog
index 5978aad9a5..f313579979 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Fri Nov 28 17:52:26 2008  Keiju Ishitsuka  <keiju@ruby-lang.org>
+
+	* lib/foerwardable.rb: should be usable def_single_delegator for
+	  Class and Module.
+	  [ruby-dev:38815]
+
 Thu Jul 16 18:28:09 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* id.c (Init_id), vm.c (vm_exec): @#__ThrowState__ is no longer
diff --git a/lib/forwardable.rb b/lib/forwardable.rb
index a4af0217d0..59a760db45 100644
--- a/lib/forwardable.rb
+++ b/lib/forwardable.rb
@@ -70,9 +70,30 @@
 #   Ruby
 #   nil
 #
-# Forwardable can be used to setup delegation at the object level as well.
+# SingleForwardable can be used to setup delegation at the object level as well.
 #
 #    printer = String.new
+#    printer.extend SingleForwardable        # prepare object for delegation
+#    printer.def_delegator "STDOUT", "puts"  # add delegation for STDOUT.puts()
+#    printer.puts "Howdy!"
+#
+# Also, SingleForwardable can be use to Class or Module.
+#
+#    module Facade
+#      extend SingleForwardable
+#      def_delegator :Implementation, :service
+#
+#      class Implementation
+#	  def service...
+#      end
+#    end
+#
+# If you want to use both Forwardable and SingleForwardable, you can
+# use methods def_instance_delegator and def_single_delegator, etc.
+# 
+# If the object isn't a Module and Class, You can too extend
+# Forwardable module. 
+#    printer = String.new
 #    printer.extend Forwardable              # prepare object for delegation
 #    printer.def_delegator "STDOUT", "puts"  # add delegation for STDOUT.puts()
 #    printer.puts "Howdy!"
@@ -111,8 +132,13 @@
 # Also see the example at forwardable.rb.
 
 module Forwardable
-  FORWARDABLE_VERSION = "1.0.0"
-  
+  FORWARDABLE_VERSION = "1.1.0"
+
+  @debug = nil
+  class<<self
+    attr_accessor :debug
+  end
+
   # Takes a hash as its argument.  The key is a symbol or an array of
   # symbols.  These symbols correspond to method names.  The value is
   # the accessor to which the methods will be delegated.
@@ -121,7 +147,7 @@ module Forwardable
   #    delegate method => accessor
   #    delegate [method, method, ...] => accessor
   #
-  def delegate(hash)
+  def instance_delegate(hash)
     hash.each{ |methods, accessor|
       methods = methods.to_s unless methods.respond_to?(:each)
       methods.each{ |method|
@@ -144,34 +170,101 @@ module Forwardable
   def def_instance_delegators(accessor, *methods)
     methods.delete("__send__")
     methods.delete("__id__")
-    methods.each{ |method|
+    for method in methods
       def_instance_delegator(accessor, method)
-    }
+    end
   end
 
-  #
-  # Defines a method _method_ which delegates to _obj_ (i.e. it calls
-  # the method of the same name in _obj_).  If _new_name_ is
-  # provided, it is used as the name for the delegate method.
-  #
   def def_instance_delegator(accessor, method, ali = method)
-    str = %Q{
+    line_no = __LINE__; str = %{
       def #{ali}(*args, &block)
-        #{accessor}.send(:#{method}, *args, &block)
+	begin
+	  #{accessor}.__send__(:#{method}, *args, &block)
+	rescue Exception
+	  $@.delete_if{|s| %r"#{Regexp.quote(__FILE__)}"o =~ s} unless Forwardable::debug
+	  ::Kernel::raise
+	end
       end
     }
-
     # If it's not a class or module, it's an instance
     begin
-      module_eval(str)
+      module_eval(str, __FILE__, line_no)
     rescue
-      instance_eval(str)
+      instance_eval(str, __FILE__, line_no)
     end
+
   end
 
+  alias delegate instance_delegate
   alias def_delegators def_instance_delegators
   alias def_delegator def_instance_delegator
 end
 
-# compatibility
-SingleForwardable = Forwardable
+#
+# Usage of The SingleForwardable is like Fowadable module.
+#
+module SingleForwardable
+  # Takes a hash as its argument.  The key is a symbol or an array of
+  # symbols.  These symbols correspond to method names.  The value is
+  # the accessor to which the methods will be delegated.
+  #
+  # :call-seq:
+  #    delegate method => accessor
+  #    delegate [method, method, ...] => accessor
+  #
+  def single_delegate(hash)
+    hash.each{ |methods, accessor|
+      methods = methods.to_s unless methods.respond_to?(:each)
+      methods.each{ |method|
+        def_single_delegator(accessor, method)
+      }
+    }
+  end
+
+  #
+  # Shortcut for defining multiple delegator methods, but with no
+  # provision for using a different name.  The following two code
+  # samples have the same effect:
+  #
+  #   def_delegators :@records, :size, :<<, :map
+  #
+  #   def_delegator :@records, :size
+  #   def_delegator :@records, :<<
+  #   def_delegator :@records, :map
+  #
+  def def_single_delegators(accessor, *methods)
+    methods.delete("__send__")
+    methods.delete("__id__")
+    for method in methods
+      def_single_delegator(accessor, method)
+    end
+  end
+
+  #
+  # Defines a method _method_ which delegates to _obj_ (i.e. it calls
+  # the method of the same name in _obj_).  If _new_name_ is
+  # provided, it is used as the name for the delegate method.
+  #
+  def def_single_delegator(accessor, method, ali = method)
+    line_no = __LINE__; str = %{
+      def #{ali}(*args, &block)
+	begin
+	  #{accessor}.__send__(:#{method}, *args, &block)
+	rescue Exception
+	  $@.delete_if{|s| %r"#{Regexp.quote(__FILE__)}"o =~ s} unless Forwardable::debug
+	  ::Kernel::raise
+	end
+      end
+    }
+
+    instance_eval(str, __FILE__, __LINE__)
+  end
+
+  alias delegate single_delegate
+  alias def_delegators def_single_delegators
+  alias def_delegator def_single_delegator
+end
+
+
+
+
diff --git a/version.h b/version.h
index 5a85815173..46fa8fc262 100644
--- a/version.h
+++ b/version.h
@@ -1,6 +1,6 @@
 #define RUBY_VERSION "1.9.1"
 #define RUBY_RELEASE_DATE "2009-07-16"
-#define RUBY_PATCHLEVEL 242
+#define RUBY_PATCHLEVEL 243
 #define RUBY_VERSION_MAJOR 1
 #define RUBY_VERSION_MINOR 9
 #define RUBY_VERSION_TEENY 1