[Python-Dev] The path module PEP

[Barry Warsaw]

On Wed, 2006-01-25 at 22:30 -0600, Ian Bicking wrote:

> IMHO the hierarchy problem is a misdesign of strings; iterating over 
> strings is usually a bug, not a deliberately used feature.  And it's a 
> particularly annoying bug, leading to weird results.

Agreed.  I've written iteration code that has to special case
basestrings before and that's particularly ugly.

> In this case a Path is not a container for characters.  Strings aren't 
> containers for characters either -- apparently they are containers for 
> smaller strings, which in turn contain themselves.  Paths might be seen 
> as a container for other subpaths, but I think everyone agrees this is 
> too ambigous and implicit.  So there's nothing sensible that __iter__ 
> can do, and having it do something not sensible (just to fill it in with 
> something) does not seem very Pythonic.
> 
> join is also a funny method that most people wouldn't expect on strings 
> anyway.  But putting that aside, the real issue I see is that it is a 
> miscognate for os.path.join, to which it has no relation.  And I can't 
> possibly imagine what you'd use it for in the context of a path.

Good points, but to me that argues against having any inheritance
relationship between strings and Paths rather than having such a
relationship and disabling certain methods.  Thomas's post seemed more
on-target for me and I'd like to see that idea fleshed out in more
detail.  If it's proved to be an impossible (or merely an extremely
infeasible) task, then I think we can discuss the shortcut of deriving
from strings.  It just seems gross so I'd like to be sure there's no
better way.

-Barry

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