Index: lib/generator.rb
===================================================================
--- lib/generator.rb	(revision 20602)
+++ lib/generator.rb	(working copy)
@@ -67,7 +67,7 @@ class Generator
   # In the latter, the given block is called with the generator
   # itself, and expected to call the +yield+ method for each element.
   def initialize(enum = nil, &block)
-    if enum
+    if @enum = enum
       @block = proc { |g|
 	enum.each { |x| g.yield x }
       }
@@ -148,6 +148,10 @@ class Generator
 
   # Rewinds the generator.
   def rewind()
+    if @enum && @enum.respond_to?(:rewind)
+      @enum.rewind
+    end
+
     initialize(nil, &@block) if @index.nonzero?
 
     self