980626

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/v1_1r@255 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 45 insertions, 1 deletions

diff --git a/lib/delegate.rb b/lib/delegate.rb
index 7889c8284f..925b4ec867 100644
--- a/lib/delegate.rb
+++ b/lib/delegate.rb
@@ -9,6 +9,12 @@
 #   foo = Object.new
 #   foo2 = SimpleDelegator.new(foo)
 #   foo.hash == foo2.hash # => true
+#
+#   Foo = DelegateClass(Array)
+#
+#  class ExtArray<DelegateClass(Array)
+#    ...
+#  end
 
 class Delegator
 
@@ -18,7 +24,7 @@ class Delegator
       preserved |= t.instance_methods
       break if t == Delegator
     end
-    preserved -= ["__getobj__","to_s","nil?","to_a","hash","dup","==","=~"]
+    preserved -= ["__getobj__","to_s","to_a","inspect","hash","eql?","==","=~","==="]
     for method in obj.methods
       next if preserved.include? method
       eval <<EOS
@@ -61,7 +67,44 @@ end
 Delegater = Delegator
 SimpleDelegater = SimpleDelegator
 
+#
+def DelegateClass(superclass)
+  klass = Class.new
+  methods = superclass.instance_methods
+  methods -= ::Kernel.instance_methods
+  methods |= ["to_s","to_a","inspect","hash","eql?","==","=~","==="]
+  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
     raise 'this is OK'
@@ -69,4 +112,5 @@ if __FILE__ == $0
   foo2 = SimpleDelegator.new(foo)
   p foo.hash == foo2.hash	# => true
   foo.test			# raise error!
+
 end