[Python-Dev] type categories

[David Abrahams]

From: "Andrew Koenig" <ark@research.att.com>


> ark> It makes me uneasy because the behavior of programs might depend
> ark> on the order in which modules are loaded.  That's why I didn't
> ark> suggest a way of defining the variations on f in separate places.
>
> David> This concern seems most un-pythonic to my eye, since there are
> David> already all kinds of ways any module can change the behavior of
> David> any call in another module. The moset direct way is by
> David> rebinding the implementation of another module's
> David> function. Python is a dynamic language, and that is usually
> David> seen as a strength.
>
> Indeed.  What concerns me is not dynamic behavior, but order-dependent
> behavior that might be occurring behind the scenes.  I would really like
> to be confident that if I write
>
>         import x, y
>
> it has the same effect as
>
>         import y, x
>
> I understand that there is no guarantee of that property now, but I
suspect
> that most people write programs in a way that does guarantee it.  I would
> hate to see the language evolve in ways that makes it substantially more
> difficult to avoid such order dependencies, so I am reluctant to propose
> a feature that would increase that difficulty.

Oh, easily solved: "in the face of ambiguity, refuse the temptation to
guess".
There should be a best match rule, and if there are two best matches, it's
an error.

-----------------------------------------------------------
           David Abrahams * Boost Consulting
dave@boost-consulting.com * http://www.boost-consulting.com