On 06/09/2011 01:22 AM, Eric Snow wrote:
Sometimes when using class inheritance, I want the overriding methods
of the subclass to get the docstring of the matching method in the
base class. You can do this with decorators (after the class
definition), with class decorators, and with metaclasses [1].
While asking for __doc__ ponies and picking colors for
bike-sheds, in a similar vein, I've occasionally wanted to do
something like
class Foo:
@property
def __doc__(self):
return dynamically_generated_string
# perhaps using introspection
This would have been most helpful in things like generating help
(like in command-line parsers), where the doc-string can
introspect the class and learn about its methods at runtime.
Some things seem to inherit, some don't, and help() doesn't seem
to pick up on any of the dynamically-defined __doc__ properties.
Test code below.
-tkc
from datetime import datetime
from sys import stdout
class Base(object):
"Base docstring"
@property
def __doc__(self):
return datetime.now().strftime('%c')
class WithDoc(Base):
"WithDoc docstring"
pass
class WithoutDoc(Base): pass
base = Base()
has = WithDoc()
lacks = WithoutDoc()
for test in (
"help(base)", # why not in help?
"help(has)", # expected
"help(lacks)", # why not in help?
"help(Base)",
"help(WithDoc)", # expected
"help(WithoutDoc)",
"stdout.write(repr(base.__doc__))", # works
"stdout.write(repr(has.__doc__))", # expected
"stdout.write(repr(lacks.__doc__))", # where'd it go?
"stdout.write(repr(Base.__doc__))", # expected
"stdout.write(repr(WithDoc.__doc__))", # expected
"stdout.write(repr(WithoutDoc.__doc__))", # what?
):
print test
eval(test)
print
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