From 210367ec889f5910e270d6ea2c7ddb8a8d939e61 Mon Sep 17 00:00:00 2001
From: matz <matz@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Wed, 20 Jan 1999 04:59:39 +0000
Subject: This commit was generated by cvs2svn to compensate for changes in
 r372, which included commits to RCS files with non-trunk default branches.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@373 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 lib/delegate.rb | 100 +++++++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 91 insertions(+), 9 deletions(-)

(limited to 'lib/delegate.rb')

diff --git a/lib/delegate.rb b/lib/delegate.rb
index e5943cead8..0771f2feeb 100644
--- a/lib/delegate.rb
+++ b/lib/delegate.rb
@@ -1,26 +1,51 @@
 #  Delegation class that delegates even methods defined in super class,
 # which can not be covered with normal method_missing hack.
 #  
-#  Delegater is the abstract delegation class. Need to redefine
-# `__getobj__' method in the subclass.  SimpleDelegater is the 
+#  Delegator is the abstract delegation class. Need to redefine
+# `__getobj__' method in the subclass.  SimpleDelegator is the 
 # concrete subclass for simple delegation.
 #
 # Usage:
 #   foo = Object.new
-#   foo = SimpleDelegater.new(foo)
-#   foo.type # => Object
+#   foo2 = SimpleDelegator.new(foo)
+#   foo.hash == foo2.hash # => true
+#
+#   Foo = DelegateClass(Array)
+#
+#  class ExtArray<DelegateClass(Array)
+#    ...
+#  end
 
-class Delegater
+class Delegator
 
   def initialize(obj)
-    preserved = ["id", "equal?", "__getobj__"]
+    preserved = ::Kernel.instance_methods
+    preserved -= ["to_s","to_a","inspect","==","=~","==="]
     for t in self.type.ancestors
       preserved |= t.instance_methods
-      break if t == Delegater
+      preserved |= t.private_instance_methods
+      preserved |= t.protected_instance_methods
+      break if t == Delegator
     end
     for method in obj.methods
       next if preserved.include? method
-      eval "def self.#{method}(*args); __getobj__.send :#{method}, *args; end"
+      eval <<-EOS
+	def self.#{method}(*args, &block)
+	  begin
+	    __getobj__.__send__(:#{method}, *args, &block)
+	  rescue Exception
+	    c = -caller(0).size
+	    if /:in `__getobj__'$/ =~ $@[c-1]  #`
+	      n = 1
+	    else
+	      c -= 1
+	      n = 2
+	    end
+	    $@[c,n] = nil
+	    raise
+	  end
+	end
+	EOS
     end
   end
 
@@ -30,7 +55,7 @@ class Delegater
 
 end
 
-class SimpleDelegater<Delegater
+class SimpleDelegator<Delegator
 
   def initialize(obj)
     super
@@ -41,4 +66,61 @@ class SimpleDelegater<Delegater
     @obj
   end
 
+  def __setobj__(obj)
+    @obj = obj
+  end
+end
+
+# backward compatibility ^_^;;;
+Delegater = Delegator
+SimpleDelegater = SimpleDelegator
+
+#
+def DelegateClass(superclass)
+  klass = Class.new
+  methods = superclass.instance_methods
+  methods -= ::Kernel.instance_methods
+  methods |= ["to_s","to_a","inspect","==","=~","==="]
+  klass.module_eval <<-EOS
+  def initialize(obj)
+    @obj = obj
+  end
+  EOS
+  for method in methods
+    klass.module_eval <<-EOS
+	def #{method}(*args, &block)
+	  begin
+	    @obj.__send__(:#{method}, *args, &block)
+	  rescue
+	    $@[0,2] = nil
+	    raise
+	  end
+	end
+	EOS
+      end
+    return klass;
+  end
+
+if __FILE__ == $0
+  class ExtArray<DelegateClass(Array)
+    def initialize()
+      super([])
+    end
+  end
+
+  ary = ExtArray.new
+  p ary.type
+  ary.push 25
+  p ary
+
+  foo = Object.new
+  def foo.test
+    25
+  end
+  def foo.error
+    raise 'this is OK'
+  end
+  foo2 = SimpleDelegator.new(foo)
+  p foo.test == foo2.test	# => true
+  foo2.error			# raise error!
 end
-- 
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