"""
doc_inherit decorator
Usage:
class Foo(object):
def foo(self):
"Frobber"
pass
class Bar(Foo):
@doc_inherit
def foo(self):
pass
Now, Bar.foo.__doc__ == Bar().foo.__doc__ == Foo.foo.__doc__ == "Frobber"
"""
from functools import wraps
class DocInherit(object):
"""
Docstring inheriting method descriptor
The class itself is also used as a decorator
"""
def __init__(self, mthd):
self.mthd = mthd
self.name = mthd.__name__
def __get__(self, obj, cls):
if obj:
return self.get_with_inst(obj, cls)
else:
return self.get_no_inst(cls)
def get_with_inst(self, obj, cls):
overridden = getattr(super(cls, obj), self.name, None)
@wraps(self.mthd, assigned=('__name__','__module__'))
def f(*args, **kwargs):
return self.mthd(obj, *args, **kwargs)
return self.use_parent_doc(f, overridden)
def get_no_inst(self, cls):
for parent in cls.__mro__[1:]:
overridden = getattr(parent, self.name, None)
if overridden: break
@wraps(self.mthd, assigned=('__name__','__module__'))
def f(*args, **kwargs):
return self.mthd(*args, **kwargs)
return self.use_parent_doc(f, overridden)
def use_parent_doc(self, func, source):
if source is None:
raise NameError, ("Can't find '%s' in parents"%self.name)
func.__doc__ = source.__doc__
return func
doc_inherit = DocInherit
