text: """
  Main program for 2to3.
  """
  
  import sys
  import os
  import logging
  import optparse
  
  from . import refactor
  
  
  class StdoutRefactoringTool(refactor.RefactoringTool):
      """
      Prints output to stdout.
      """
  
      def log_error(self, msg, *args, **kwargs):
          self.errors.append((msg, args, kwargs))
          self.logger.error(msg, *args, **kwargs)
  
      def print_output(self, lines):
          for line in lines:
              print line
  
  
  def main(fixer_pkg, args=None):
      """Main program.
  
      Args:
          fixer_pkg: the name of a package where the fixers are located.
          args: optional; a list of command line arguments. If omitted,
                sys.argv[1:] is used.
  
      Returns a suggested exit status (0, 1, 2).
      """
      # Set up option parser
      parser = optparse.OptionParser(usage="refactor.py [options] file|dir ...")
      parser.add_option("-d", "--doctests_only", action="store_true",
                        help="Fix up doctests only")
      parser.add_option("-f", "--fix", action="append", default=[],
                        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("-p", "--print-function", action="store_true",
                        help="Modify the grammar so that print() is a function")
      parser.add_option("-v", "--verbose", action="store_true",
                        help="More verbose logging")
      parser.add_option("-w", "--write", action="store_true",
                        help="Write back modified files")
  
      # Parse command line arguments
      refactor_stdin = False
      options, args = parser.parse_args(args)
      if options.list_fixes:
          print "Available transformations for the -f/--fix option:"
          for fixname in refactor.get_all_fix_names(fixer_pkg):
              print fixname
          if not args:
              return 0
      if not args:
          print >>sys.stderr, "At least one file or directory argument required."
          print >>sys.stderr, "Use --help to show usage."
          return 2
      if "-" in args:
          refactor_stdin = True
          if options.write:
              print >>sys.stderr, "Can't write to stdin."
              return 2
  
      # Set up logging handler
      level = logging.DEBUG if options.verbose else logging.INFO
      logging.basicConfig(format='%(name)s: %(message)s', level=level)
  
      # Initialize the refactoring tool
      rt_opts = {"print_function" : options.print_function}
      avail_names = refactor.get_fixers_from_package(fixer_pkg)
      explicit = []
      if options.fix:
          explicit = [fixer_pkg + ".fix_" + fix
                      for fix in options.fix if fix != "all"]
          fixer_names = avail_names if "all" in options.fix else explicit
      else:
          fixer_names = avail_names
      rt = StdoutRefactoringTool(fixer_names, rt_opts, explicit=explicit)
  
      # Refactor all files and directories passed as arguments
      if not rt.errors:
          if refactor_stdin:
              rt.refactor_stdin()
          else:
              rt.refactor(args, options.write, options.doctests_only)
          rt.summarize()
  
      # Return error status (0 if rt.errors is zero)
      return int(bool(rt.errors))
  