[Python-ideas] Trial balloon: adding variable type declarations in support of PEP 484

[Guido van Rossum]

On Mon, Aug 8, 2016 at 11:17 PM, Greg Ewing <greg.ewing at canterbury.ac.nz>
wrote:

> אלעזר wrote:
>
>> class Starship(tuple):
>>     damage: int = 0      captain: str  = "Kirk"
>>
>> Is an obvious syntax for
>>     Starship = NamedTuple('Starship', [('damage', int), ('captain', str)])
>>
>
> But the untyped version of that already has a meaning --
> it's a tuple subclass with two extra class attributes
> that are unrelated to its indexable items.
>
> I thought that type annotations weren't meant to change
> runtime semantics?


Correct, but we can invent a new base class that has these semantics. It's
no different from Enum.

Anyway, I think this will have to be an add-on to be designed after the
basics are done.

-- 
--Guido van Rossum (python.org/~guido)
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