Verbose and flexible args and kwargs syntax

[Eelco]

On 13 dec, 12:28, Steven D'Aprano <steve
+comp.lang.pyt... at pearwood.info> wrote:
> On Tue, 13 Dec 2011 02:46:13 -0800, Eelco wrote:
> > With all this being said, I must say that the notion of indtroducing
> > type constraints into Python is quite a radical one*,
>
> Not that radical. Here's the creator of Python musing about adding
> optional type checks to Python:
>
> http://www.artima.com/weblogs/viewpost.jsp?thread=85551http://www.artima.com/weblogs/viewpost.jsp?thread=86641http://www.artima.com/weblogs/viewpost.jsp?thread=87182

Good find; but still radical enough that it hasnt been implemented.
Note that these musing are trying to adress a yet far more general
problem of specifying arbitrary types constraints on anything; I am
primarily interested in specifying container types in the special case
of collection packing/unpacking syntax, with further extensions
nothing but a welcome addon. The fact that the former was judged
infeasible does not mean the more modest goal of the latter might not
be attainable.


> > *even though the asteriks syntax is infact a limited form of exactly
> > that
>
> It absolutely is not. def f(*args, **kwargs) constructs a tuple and a
> dict, it does not type-check that the function is passed a tuple and a
> dict as arguments. These are completely different things.

Which is of course not something I ever proposed; I never said
anything about checking types of existing data; im talking about
coercing types of newly created data, like the target of a collection
packing. That is exactly what *args and **kwargs also do.