[Python-Dev] Re: Re: PEP 318: Decorators last before colon (original) (raw)

Terry Reedy tjreedy at udel.edu
Thu Apr 1 11:16:31 EST 2004

"Peter Norvig" <pnorvig at google.com> wrote in message news:42B02151.420DCBB8 at mail.google.com...

I have to say I favor the "last before colon" approach,

The way I see it today, we are trying to select syntax to define something like a 'function metatype' (FMT) in order to get non-standard function-like objects. The idea and result strike me as similar (but not identical) to running the pieces of a would-be class thru a metaclass. If FMTs were required to be defined and named before use, then [FMTidentifier] would be analogous to metaclass = MCidentifier after a class statement. While a metaclass can be defined in-place, over multiple lines, this does not work nearly so well for an anonymous FMT.

(Has any consideration been given to an actual metafunc mechanism more directly analogous to metaclasses, that would be given the pieces of a would-be function (name, param names, default args, code body, etc), so that there would not necessarily ever be a standard function object?)

but if it has to be before the def, then I think it should have a keyword,

Yes. My support for 'as' was based on misremembering its quasi status.

and if you don't want to introduce a new keyword, then it looks like "is" is the only reasonable candidate. And if you do have a keyword, you don't need the square brackets.

Since the sequence is not going to be mutated, I would see them as a positive distraction.

So you have

is: classmethod def f(x): pass

is: author("Guido"), signature(int, result=None) def g(x): pass

For this usage, 'is' is semantically better than 'as' anyway.

Terry J. Reedy

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