Source code for pyrocore.util.algo

# -*- coding: utf-8 -*-
# pylint: disable=
""" Helper Algorithms.

    Copyright (c) 2009, 2010 The PyroScope Project <pyroscope.project@gmail.com>
"""
# 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.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
from __future__ import absolute_import

import logging

log = logging.getLogger(__name__)


try:
    from itertools import product # @UnusedImport pylint: disable=E0611
except ImportError:
    def product(*args, **kwds):
        """ product('ABCD', 'xy') --> Ax Ay Bx By Cx Cy Dx Dy
            product(range(2), repeat=3) --> 000 001 010 011 100 101 110 111
        """
        pools = map(tuple, args) * kwds.get('repeat', 1)
        result = [[]]
        for pool in pools:
            result = [x+[y] for x in result for y in pool]
        for prod in result:
            yield tuple(prod)


[docs]def flatten(nested, containers=(list, tuple)): """ Flatten a nested list in-place and return it. """ flat = list(nested) # handle iterators / generators i = 0 while i < len(flat): while isinstance(flat[i], containers): if not flat[i]: # kill empty list flat.pop(i) # inspect new 'i'th element in outer loop i -= 1 break else: flat[i:i + 1] = (flat[i]) # 'i'th element is scalar, proceed i += 1 return flat
[docs]class AttributeMapping(object): """ Wrap an object's dict so that it can be accessed by the mapping protocol. """ def __init__(self, obj, defaults=None): """ Store object we want to map, and any default values. @param obj: the wrapped object @type obj: object @param defaults: default values @type defaults: dict """ self.obj = obj self.defaults = defaults or {} def __getitem__(self, key): """ Return object attribute named C{key}. """ ##print "GETITEM", key, self.defaults try: return getattr(self.obj, key) except AttributeError as exc: try: return self.defaults[key] except KeyError: raise AttributeError("%s for %r.%s" % (exc, self.obj, key))