Lib/importlib.py

   1 """Backport of importlib.import_module from 3.x."""
   2 import sys
   3
   4 def _resolve_name(name, package, level):
   5     """Return the absolute name of the module to be imported."""
   6     level -= 1
   7     try:
   8         if package.count('.') < level:
   9             raise ValueError("attempted relative import beyond top-level "
  10                               "package")
  11     except AttributeError:
  12         raise ValueError("__package__ not set to a string")
  13     base = package.rsplit('.', level)[0]
  14     if name:
  15         return "{0}.{1}".format(base, name)
  16     else:
  17         return base
  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]