Mercurial > hg
view mercurial/thirdparty/zope/interface/ro.py @ 37179:49630e75635d
thirdparty: allow zope.interface.advice to be lazily imported
The symbol from this module is only used in functions. Let's access
that symbol through its imported module so importing
zope.interface.advice can be lazy.
Differential Revision: https://phab.mercurial-scm.org/D2931
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Wed, 21 Mar 2018 18:13:40 -0700 |
parents | 68ee61822182 |
children |
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############################################################################## # # Copyright (c) 2003 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. # ############################################################################## """Compute a resolution order for an object and its bases """ from __future__ import absolute_import __docformat__ = 'restructuredtext' def _mergeOrderings(orderings): """Merge multiple orderings so that within-ordering order is preserved Orderings are constrained in such a way that if an object appears in two or more orderings, then the suffix that begins with the object must be in both orderings. For example: >>> _mergeOrderings([ ... ['x', 'y', 'z'], ... ['q', 'z'], ... [1, 3, 5], ... ['z'] ... ]) ['x', 'y', 'q', 1, 3, 5, 'z'] """ seen = {} result = [] for ordering in reversed(orderings): for o in reversed(ordering): if o not in seen: seen[o] = 1 result.insert(0, o) return result def _flatten(ob): result = [ob] i = 0 for ob in iter(result): i += 1 # The recursive calls can be avoided by inserting the base classes # into the dynamically growing list directly after the currently # considered object; the iterator makes sure this will keep working # in the future, since it cannot rely on the length of the list # by definition. result[i:i] = ob.__bases__ return result def ro(object): """Compute a "resolution order" for an object """ return _mergeOrderings([_flatten(object)])