[Python-3000] Discussions with no PEPs

[Benji York]

Phillip J. Eby wrote:
> In short, the very idea of 'is_file()' is wrong, wrong, wrong.  At least, 
> if your goal is to make libraries more robust and reusable.

First a note: I personally hope a generic function system (with multiple 
dispatch) makes it into 3.0 and I don't particularly like the ABC proposal.

Having said that, the origin of this discussion was (paraphrased) 
"instead of doing ABCs, let's just do interfaces".  Which seems 
reasonably to me.

It would seem that the same arguments against is_file (or any other 
check of that ilk) would apply to the ABCs proposed 
(http://wiki.python.org/moin/AbstractBaseClasses) as well, but I don't 
recall much argument about the idea that ability to check for a few 
basic types should be included in the language.

If that idea isn't widely accepted, I would have expected more vigorous 
argument (from many corners) now that it seems ABCs are destined to 
appear in 3.0.

If 3.0 /is/ going to give the "typecheck" ability to basic types, then 
the argument is: should it be ABCs, interfaces, generic functions, or 
something else.
-- 
Benji York
http://benjiyork.com