Lib/importlib/__init__.py

   1 """Backport of importlib.import_module from 3.x."""
   2 # While not critical (and in no way guaranteed!), it would be nice to keep this
   3 # code compatible with Python 2.3.
   4 import sys
   5
   6 def _resolve_name(name, package, level):
   7     """Return the absolute name of the module to be imported."""
   8     if not hasattr(package, 'rindex'):
   9         raise ValueError("'package' not set to a string")
  10     dot = len(package)
  11     for x in xrange(level, 1, -1):
  12         try:
  13             dot = package.rindex('.', 0, dot)
  14         except ValueError:
  15             raise ValueError("attempted relative import beyond top-level "
  16                               "package")
  17     return "%s.%s" % (package[:dot], name)
  18
  19
  20 def import_module(name, package=None):
  21     """Import a module.
  22
  23     The 'package' argument is required when performing a relative import. It
  24     specifies the package to use as the anchor point from which to resolve the
  25     relative import to an absolute import.
  26
  27     """
  28     if name.startswith('.'):
  29         if not package:
  30             raise TypeError("relative imports require the 'package' argument")
  31         level = 0
  32         for character in name:
  33             if character != '.':
  34                 break
  35             level += 1
  36         name = _resolve_name(name[level:], package, level)
  37     __import__(name)
  38     return sys.modules[name]