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

[George Sakkis]

On Jul 5, 3:24 pm, Donn Cave <d... at u.washington.edu> wrote:
> In article <1183575597.272150.152... at w5g2000hsg.googlegroups.com>,
>  Paul Boddie <p... at boddie.org.uk> wrote:
>
> > However, it's interesting to consider the work that sometimes needs to
> > go in to specify data structures in some languages - thinking of ML
> > and friends, as opposed to Java and friends. The campaign for optional
> > static typing in Python rapidly became bogged down in this matter,
> > fearing that any resulting specification for type information might
> > not be the right combination of flexible and powerful to fit in with
> > the rest of the language, and that's how we really ended up with PEP
> > 3107: make the semantics vague and pretend it has nothing to do with
> > types, thus avoiding the issue completely.
>
> I missed the campaign for optional static typing, must have been
> waged in the developer list.  Unless it was not much more than
> some on-line musings from GvR a year or two ago.  I don't see
> how it could ever get anywhere without offending a lot of the
> Python crowd, however well designed, so I can see why someone
> might try to sneak it past by pretending it has nothing to do
> with types.  But he didn't -- look at the examples, I think he
> rather overstates the potential for static typing applications.

The key point is that this is left to 3rd party libraries; the
language won't know anything more about static typing than it does
now. FWIW, there is already a typechecking module [1] providing a
syntax as friendly as it gets without function annotations. If the
number of its downloads from the Cheeshop is any indication of static
typing's popularity among Pythonistas, I doubt that PEP 3107 will give
significant momentum to any non-standard module anytime soon.

George


[1] http://oakwinter.com/code/typecheck/