PEP 3107 and stronger typing (note: probably a newbie question)

[Kay Schluehr]

On 22 Jun., 08:46, John Nagle <n... at animats.com> wrote:

> PEP 3107 seems to add negative value to the language.  The
> ability to add arbitrary attributes to parameters which can then
> be interpreted by some external library yet to be defined is
> a "l33t feature", one that's more cute than useful.  Type-based
> dispatching is cute, but not really essential to Python.

I guess you refer to the generic functions PEP. Otherwise type based
dispatching is what Psyco does implicitely by caching variants of
natively compiled code blocks that can be considered as anonymous
functions. But then Psyco has to perform continous measurements and
either select a precompiled block if an appropriate signature has been
found or return code to the bytecode interpreter for further
evaluation. This scheme is an example for type directed evaluation
that does not interfere with Pythons default semantics.

Personally I appreciate having more control over expressions by means
of annotations. I also do think it's valuable for component adaptions.
So far I fail to see why it shall harm Python or having any impact on
its flexibility. Being "unusal" is not an argument neither are vague
apprehensions that Python will be locked into a poor type system with
rigid default semantics.

Kay