[Python-Dev] PyPy, Jython, & IronPython: Enum convenience function and pickleablity

[Eli Bendersky]

> > > On Thu, 2 May 2013 13:15:00 -0700
> > > Eli Bendersky <eliben at gmail.com> wrote:
> > > > > Two things that were suggested in private:
> > > > >
> > > > > 1) ask users to pass the module name to the convenience function
> > > > > explicitly (i.e. pass "seasonmodule.Season" instead of "Season" as
> the
> > > > > class "name"). Guido doesn't like it :-)
> > > > >
> > > > > 2) dicth the "convenience function" and replace it with a regular
> > > > > class-based syntax. Ethan doesn't like it :-)
> > > > >
> > > >
> > > > Re (2), we already have the hack in stdlib in namedtuple, so not
> allowing
> > > > it for an enum is a step backwards.
> > >
> > > That's a fallacy. There is no step backwards if you adopt a class-based
> > > syntax, which is just as convenient as the proposed "convenience
> > > function". I have a hard time understanding that calling a function to
> > > declare a class is suddenly considered "convenient".
> > >
> > > > If
> > > > sys._getframe(1).f_globals['__name__'] feels hackish, maybe it can be
> > > > shortened to a convenience function the stdlib provides?
> > >
> > > It's not the notation which is hackish, it's the fact that you are
> > > inspecting the frame stack in the hope of getting the right
> information.
> > >
> > > What if someone wants to write another convenience function that wraps
> > > your convenience function? What if your code is executing from some
> > > kind of step-by-step debugger which inserts an additional frame in the
> > > call stack? What if someone wants the enum to be nested inside another
> > > class (rather than reside at the module top-level)?
> > >
> >
> > Would nesting the non-convenience Enum in a function or a class allow one
> > to pickle it?
>
> Once PEP 3154 is implemented (Alexandre is on it :-)), nested classes
> should be picklable.


Interesting, I did not know that.


> As for classes inside functions, it sounds quite
> impossible (how do you instantiate the function namespace without
> calling the function?).
>

True.

Back to my question from before, though - do we have a real technical
limitation of having something like inspect.what_module_am_i_now_in()
that's supposed to work for all Python code?

Eli
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