cybertools/index/multikey.py
helmutm 430fdd30d0 MultiKeyDict re-implemented
git-svn-id: svn://svn.cy55.de/Zope3/src/cybertools/trunk@1514 fd906abe-77d9-0310-91a1-e0d9ade77398
2006-11-22 11:46:10 +00:00

82 lines
2.7 KiB
Python

#
# Copyright (c) 2006 Helmut Merz helmutm@cy55.de
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#
"""
Dictionaries with multiple keys.
$Id$
"""
_not_found = object()
class MultiKeyDict(dict):
def __init__(self, keylen=None, **kw):
super(MultiKeyDict, self).__init__(**kw)
self.submapping = {}
self.keylen = keylen
def __setitem__(self, key, value):
assert type(key) is tuple
if self.keylen is None:
self.keylen = len(key)
assert len(key) == self.keylen
k0 = key[0]
if len(key) > 1:
sub = self.submapping.setdefault(k0, MultiKeyDict())
sub[key[1:]] = value
base = super(MultiKeyDict, self).__setitem__(k0, value)
def __getitem__(self, key):
r = self.get(key, _not_found)
if r is _not_found:
raise KeyError(key)
return r
def get(self, key, default=None):
assert type(key) is tuple
assert len(key) == self.keylen
k0 = key[0]
rsub = _not_found
r0 = super(MultiKeyDict, self).get(k0, _not_found)
if r0 is _not_found:
r0 = self.getFallback(k0)
if r0 is _not_found:
return default
if len(key) > 1:
sub = self.submapping.get(k0, _not_found)
if sub is _not_found:
sub = self.getSubmappingFallback(key)
if sub is _not_found:
rsub = _not_found
else:
rsub = sub.get(key[1:], _not_found)
if rsub is _not_found:
return default
result = rsub is _not_found and r0 or rsub
return result is _not_found and default or result
def getFallback(self, key):
return super(MultiKeyDict, self).get(None, _not_found)
def getSubmappingFallback(self, key):
return self.submapping.get(None, _not_found)
def __repr__(self):
return ('<MultiKeyDict %s; submapping: %s>'
% (super(MultiKeyDict, self).__repr__(), `self.submapping`))