[Python-3000] Parameter types and multiple method dispatch

[Giovanni Bajo]

Greg Ewing wrote:

>> Guido's original proposal called for __typecheck__(arg, type) to
>> be called on each argument that has a type declaration, with the
>> result replacing the argument value.
>>
>> Given this definition for the semantics, none of the issues you
>> raised are relevant.
>
> I think some of it is still relevant, such as the concern
> about different parts of the same program fighting over
> the interpretation of the type annotations.
>
> I'm rather leery about the whole thing myself because of
> that. The idea of adding something in such a fundamental
> and intrusive way to the language when we don't even
> have a clear idea of what we're going to use it for
> smells very bad to me.

Another thing I totally don't understand is how type annotations without any
semantic assigned to them can be used to help speeding up Python and its
compiler/interpreter. I thought (and hoped) that was one of the main scopes
of type annotations.
-- 
Giovanni Bajo