Source code for zope.dottedname.resolve

##############################################################################
#
# Copyright (c) 2004 Zope Foundation and Contributors.
# All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE.
#
##############################################################################
"""Dotted name support
"""




def resolve(name, module=None):
    """Resolve ``name`` to a Python object via imports / attribute lookups.

    If ``module`` is None, ``name`` must be "absolute" (no leading dots).

    If ``module`` is not None, and ``name`` is "relative" (has leading dots),
    the object will be found by navigating relative to ``module``.

    Returns the object, if found.  If not, propagates the error.
    """
    name = name.split('.')
    if not name[0]:
        if module is None:
            raise ValueError("relative name without base module")
        module = module.split('.')
        name.pop(0)
        while not name[0]:
            module.pop()
            name.pop(0)
        name = module + name

    used = name.pop(0)
    found = __import__(used)
    for n in name:
        used += '.' + n
        try:
            found = getattr(found, n)
        except AttributeError:
            __import__(used)
            found = getattr(found, n)

    return found