Limnoria/src/fix.py

###
# Copyright (c) 2002-2004, Jeremiah Fincher
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
#   * Redistributions of source code must retain the above copyright notice,
#     this list of conditions, and the following disclaimer.
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#     this list of conditions, and the following disclaimer in the
#     documentation and/or other materials provided with the distribution.
#   * Neither the name of the author of this software nor the name of
#     contributors to this software may be used to endorse or promote products
#     derived from this software without specific prior written consent.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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# POSSIBILITY OF SUCH DAMAGE.
###

"""
Fixes stuff that Python should have but doesn't.
"""

from __future__ import division

__revision__ = "$Id$"

__all__ = []

exported = ['ignore', 'window', 'group', 'partition',
            'any', 'all', 'rsplit', 'dynamic']

import sys
import new
import atexit
import string
string.ascii = string.maketrans('', '')

import random
_choice = random.choice
def choice(iterable):
    if isinstance(iterable, (list, tuple)):
        return _choice(iterable)
    else:
        n = 1
        m = new.module('') # Guaranteed unique value.
        ret = m
        for x in iterable:
            if random.random() < 1/n:
                ret = x
            n += 1
        if ret is m:
            raise IndexError
        return ret
random.choice = choice

def ignore(*args, **kwargs):
    """Simply ignore the arguments sent to it."""
    pass

class DynamicScope(object):
    def _getLocals(self, name):
        f = sys._getframe().f_back.f_back # _getLocals <- __[gs]etattr__ <- ...
        while f:
            if name in f.f_locals:
                return f.f_locals
            f = f.f_back
        raise NameError, name
    
    def __getattr__(self, name):
        return self._getLocals(name)[name]

    def __setattr__(self, name, value):
        self._getLocals(name)[name] = value
dynamic = DynamicScope()
        

if sys.version_info < (2, 4, 0):
    def reversed(L):
        """Iterates through a sequence in reverse."""
        for i in xrange(len(L) - 1, -1, -1):
            yield L[i]
    exported.append('reversed')

def window(L, size):
    """Returns a sliding 'window' through the list L of size size."""
    assert not isinstance(L, int), 'Argument order swapped: window(L, size)'
    if size < 1:
        raise ValueError, 'size <= 0 disallowed.'
    for i in xrange(len(L) - (size-1)):
        yield L[i:i+size]

import itertools
def ilen(iterable):
    """Returns the length of an iterator."""
    i = 0
    for _ in iterable:
        i += 1
    return i

def trueCycle(iterable):
    while 1:
        yielded = False
        for x in iterable:
            yield x
            yielded = True
        if not yielded:
            raise StopIteration

itertools.trueCycle = trueCycle
itertools.ilen = ilen

def groupby(key, iterable):
    if key is None:
        key = lambda x: x
    it = iter(iterable)
    value = it.next() # If there are no items, this takes an early exit
    oldkey = key(value)
    group = [value]
    for value in it:
        newkey = key(value)
        if newkey != oldkey:
            yield group
            group = []
            oldkey = newkey
        group.append(value)
    yield group
itertools.groupby = groupby

def group(seq, groupSize, noneFill=True):
    """Groups a given sequence into sublists of length groupSize."""
    ret = []
    L = []
    i = groupSize
    for elt in seq:
        if i > 0:
            L.append(elt)
        else:
            ret.append(L)
            i = groupSize
            L = []
            L.append(elt)
        i -= 1
    if L:
        if noneFill:
            while len(L) < groupSize:
                L.append(None)
        ret.append(L)
    return ret

def partition(p, L):
    """Partitions a list L based on a predicate p.  Returns a (yes,no) tuple"""
    no = []
    yes = []
    for elt in L:
        if p(elt):
            yes.append(elt)
        else:
            no.append(elt)
    return (yes, no)

def any(p, seq):
    """Returns true if any element in seq satisfies predicate p."""
    for elt in itertools.ifilter(p, seq):
        return True
    else:
        return False

def all(p, seq):
    """Returns true if all elements in seq satisfy predicate p."""
    for elt in itertools.ifilterfalse(p, seq):
        return False
    else:
        return True

def rsplit(s, sep=None, maxsplit=-1):
    """Equivalent to str.split, except splitting from the right."""
    if sys.version_info < (2, 4, 0):
        if sep is not None:
            sep = sep[::-1]
        L = s[::-1].split(sep, maxsplit)
        L.reverse()
        return [s[::-1] for s in L]
    else:
        return s.rsplit(sep, maxsplit)

if sys.version_info < (2, 4, 0):
    import operator
    def itemgetter(i):
        return lambda x: x[i]

    def attrgetter(attr):
        return lambda x: getattr(x, attr)
    operator.itemgetter = itemgetter
    operator.attrgetter = attrgetter

import csv
import cStringIO as StringIO
def join(L):
    fd = StringIO.StringIO()
    writer = csv.writer(fd)
    writer.writerow(L)
    return fd.getvalue().rstrip('\r\n')

def split(s):
    fd = StringIO.StringIO(s)
    reader = csv.reader(fd)
    return reader.next()
csv.join = join
csv.split = split

import socket
# Some socket modules don't have sslerror, so we'll just make it an error.
if not hasattr(socket, 'sslerror'):
    socket.sslerror = socket.error

# Trick to get an __revision__ attribute in all exceptions, if possible.
if not hasattr(Exception, '_original__init__'):
    Exception._original__init__ = Exception.__init__
    def __init__(self, *args, **kwargs):
        # We had sys._getframe(1) here for awhile, but in the interactive
        # interpreter, there isn't enough call stack.  Thanks, Rafterman, for
        # pointing that out.
        me = sys._getframe(0)
        caller = me.f_back
        callerGlobals = getattr(caller, 'f_globals', {})
        callerModule = sys.modules.get(callerGlobals.get('__name__'))
        self.__revision__ = getattr(callerModule, '__revision__', None)
        self._original__init__(*args, **kwargs)
    Exception.__init__ = __init__

# Apparently, some things get dismantled a bit early, and we can get stuck in
# a non-exiting loop because our Exception.__init__ raises an exception.  This
# makes sure that we replace our __init__ with the original before things like
# the sys module are dismantled.
def _replace_original__init__():
    Exception.__init__ = Exception._original__init__
atexit.register(_replace_original__init__)

g = globals()
for name in exported:
    __builtins__[name] = g[name]



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