[Python-Dev] (no subject)

Michael Chermside mcherm at mcherm.com
Mon Mar 14 14:34:57 CET 2005

Nick Coghlan writes:

> Patch against current CVS added to SF with the behaviour:
>    def update_meta(self, other):
>      self.__name__ = other.__name__
>      self.__doc__ = other.__doc__
>      self.__dict__.update(other.__dict__)

Nice... thanks. But I have to ask: is this really the right set of metadata to
be updating? Here are a few things that perhaps ought be copied by update_meta:

    f.__name__     (already included)
    f.__doc__      (already included)
    f.__dict__     (already included)
    f.__module__   (probably should include)
    f.func_code.co_filename     (to match f.__name__, but I'd leave it alone)

there's also the annoying fact that in IDLE (and in some other python-aware
IDEs) one can see the argument signature for a function as a "tool tip"
or other hint. Very handy that, but if a decorator is applied then all
you will see is "func(*args, **kwargs)" which is less than helpful. I'm
not sure whether this CAN be duplicated... I believe it is generated by
examining the following:

    f.func_code.co_flags & 0x4
    f.func_code.co_flags & 0x8

...and I suspect (experimentation seems to confirm this) that if you mangle
these then the code object won't work correctly. If anyone's got a
suggestion for fixing this, I'd love to hear it.

-- Michael Chermside

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