=== modified file 'lib2to3/refactor.py'
--- lib2to3/refactor.py	2008-07-16 18:28:19 +0000
+++ lib2to3/refactor.py	2008-07-25 20:25:29 +0000
@@ -20,6 +20,8 @@
 import logging
 from collections import defaultdict
 from itertools import chain
+from processing import Process
+from tempfile import TemporaryFile
 
 # Local imports
 from .pgen2 import driver
@@ -48,6 +50,8 @@
                       help="Each FIX specifies a transformation; default all")
     parser.add_option("-l", "--list-fixes", action="store_true",
                       help="List available transformations (fixes/fix_*.py)")
+    parser.add_option("-n", "--num-processes", action="store", type="int", 
+                      default=1, help="Specifies number of processes to make")
     parser.add_option("-p", "--print-function", action="store_true",
                       help="Modify the grammar so that print() is a function")
     parser.add_option("-v", "--verbose", action="store_true",
@@ -243,6 +247,9 @@
 
         Files and subdirectories starting with '.' are skipped.
         """
+        # keep track of children if this is going to be multiprocess
+        if self.options.num_processes > 1:
+            children = []
         for dirpath, dirnames, filenames in os.walk(arg):
             if self.options.verbose:
                 self.log_message("Descending into %s", dirpath)
@@ -251,9 +258,45 @@
             for name in filenames:
                 if not name.startswith(".") and name.endswith("py"):
                     fullname = os.path.join(dirpath, name)
-                    self.refactor_file(fullname)
+                    if self.options.num_processes > 1:
+                        children = self.refactor_parent(fullname, children)
+                    else:
+                        self.refactor_file(fullname)
             # Modify dirnames in-place to remove subdirs with leading dots
             dirnames[:] = [dn for dn in dirnames if not dn.startswith(".")]
+        # Print the results from all remaining children
+        if self.options.num_processes > 1:
+            self.print_child(children, 1)
+    
+    def print_child(self, children, max):
+        """ Joins and prints children until there are only max children
+            left in the children list. Returns this list."""
+        while len(children) >= max:
+            for child, pipe, filename in children:
+                child.join(0.1) # is this a reasonable timeout?
+                if not child.isAlive():
+                    pipe.seek(0)
+                    results = pipe.read()
+                    if results:
+                        print results
+                        self.files.append(filename)
+                    children.remove((child, pipe, filename))
+                    break
+        return children
+
+    def refactor_parent(self, filename, children):
+        """ Parent process that farms refactoring out to child processes."""
+        children = self.print_child(children, self.options.num_processes)
+        pipe = TemporaryFile()
+        child = Process(target=self.refactor_child, args=[filename, pipe])
+        children.append((child, pipe, filename))
+        child.start()
+        return children
+        
+    def refactor_child(self, filename, pipe):
+        """ Wrapper for refactor_file that redirects output to pipe."""
+        sys.stdout = pipe
+        self.refactor_file(filename)
 
     def refactor_file(self, filename):
         """Refactors a file."""