Revision: 3082
at June 1, 2007 20:24 by n3x

Updated Code
```class Singleton(type):
def __init__(self, *args, **kwds):
type.__init__(self, *args, **kwds)
self._instances = {}

def __call__(self, *args, **kwds):
sig = args + tuple(sorted(kwds.items()))
if not sig in self._instances:
self._instances[sig] = type.__call__(self, *args, **kwds)
return self._instances[sig]```

Revision: 3081
at June 1, 2007 20:20 by n3x

Updated Code
```class Singleton(type):
def __init__(self, *args, **kwds):
type.__init__(self, *args, **kwds)
self._instances = {}

def __call__(self, *args, **kwds):
sig = args + tuple(sorted(kwds.values()))
if not sig in self._instances:
self._instances[sig] = type.__call__(self, *args, **kwds)
return self._instances[sig]```

Revision: 3080
at June 1, 2007 20:11 by n3x

Updated Code
```class Singleton(type):
def __init__(self, *args, **kwds):
type.__init__(self, *args, **kwds)
self._instances = {}

def __call__(self, *args, **kwds):
sig = args + tuple(dictToList(kwds))
if not sig in self._instances:
self._instances[sig] = type.__call__(self, *args, **kwds)
return self._instances[sig]

def dictToList(dict):
""" dictionaries have the values() method, but two equivalent dicts may
return differently ordered lists. this function sorts by dictionary
keys in order to eliminate that problem.
"""
keys = dict.keys()
keys.sort()
values = [dict[k] for k in keys]
return zip(keys, values)```

Revision: 3079
at June 1, 2007 20:07 by n3x

Initial Code
```class Singleton(type):
def __init__(self, *args, **kwds):
type.__init__(self, *args, **kwds)
self._instances = {}

def __call__(self, *args, **kwds):
if len(kwds) > 0:
sig = args + tuple(dictToList(kwds))
else:
sig = args
if not sig in self._instances:
self._instances[sig] = type.__call__(self, *args, **kwds)
return self._instances[sig]

def dictToList(dict):
""" dictionaries have the values() method, but two equivalent dicts may
return differently ordered lists. this function sorts by dictionary
keys in order to eliminate that problem.
"""
keys = dict.keys()
keys.sort()
values = [dict[k] for k in keys]
return zip(keys, values)```

Initial URL

Initial Description
```The ASPN cookbook has many recipes for singletons in Python. So far, this one
http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/412551
has been my favourite, because it is so simple and concise. However, I just ran into a brick wall when I tried to use it with a class that can be initialized with keyword arguments. This is my first draft for a solution to this problem. It's quick and dirty; please give it a glance and leave a comment if you find a problem.```

Initial Title
`Making Daniel Brodie's singleton recipe work with keyword arguments`

Initial Tags
`python`

Initial Language
`Python`