[Python-Dev] PEP 318 - generality of list; restrictions on elements

[Michael Hudson]

Barry Warsaw <barry at python.org> writes:

> On Mon, 2004-03-08 at 15:46, Skip Montanaro wrote:
>
>> I guess this is an area where PEP 318 should be fleshed out a bit.  I don't
>> see any reason it shouldn't be expanded to include semantics as well as
>> syntax.  That might require a title change, but I don't think the semantics
>> should be left unspecified, nor do I think the syntax and semantics should
>> reside in separate PEPs.
>
> I agree.  FWIW, I think the list of things inside the square brackets
> should be simple identifiers, i.e. the names of callables that have been
> defined elsewhere.  

I think this is a bad idea, as Skip says.

You can do this today:

class C(random.choice([list, object, dict))):
    pass

Doesn't mean people do, though.

> I'd prefer to keep them simple, meaning no lambdas or list
> comprehensions.  But that's just me.

I'm opposed to arbitrary restrictions.

Cheers,
mwh

-- 
     ARTHUR:  Why are there three of you?
  LINTILLAS:  Why is there only one of you?
     ARTHUR:  Er... Could I have notice of that question?
                   -- The Hitch-Hikers Guide to the Galaxy, Episode 11