Viewing file:  classinit.py (1.81 KB) -rw-r--r--
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# (c) 2005 Ian Bicking and contributors; written for Paste (http://pythonpaste.org)
# Licensed under the MIT license: http://www.opensource.org/licenses/mit-license.php
class ClassInitMeta(type):
def __new__(meta, class_name, bases, new_attrs):
cls = type.__new__(meta, class_name, bases, new_attrs)
if (new_attrs.has_key('__classinit__')
and not isinstance(cls.__classinit__, staticmethod)):
setattr(cls, '__classinit__',
staticmethod(cls.__classinit__.im_func))
if hasattr(cls, '__classinit__'):
cls.__classinit__(cls, new_attrs)
return cls
def build_properties(cls, new_attrs):
"""
Given a class and a new set of attributes (as passed in by
__classinit__), create or modify properties based on functions
with special names ending in __get, __set, and __del.
"""
for name, value in new_attrs.items():
if (name.endswith('__get') or name.endswith('__set')
or name.endswith('__del')):
base = name[:-5]
if hasattr(cls, base):
old_prop = getattr(cls, base)
if not isinstance(old_prop, property):
raise ValueError(
"Attribute %s is a %s, not a property; function %s is named like a property"
% (base, type(old_prop), name))
attrs = {'fget': old_prop.fget,
'fset': old_prop.fset,
'fdel': old_prop.fdel,
'doc': old_prop.__doc__}
else:
attrs = {}
attrs['f' + name[-3:]] = value
if name.endswith('__get') and value.__doc__:
attrs['doc'] = value.__doc__
new_prop = property(**attrs)
setattr(cls, base, new_prop)
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