[Python-Dev] Re: Christmas Wishlist

[Barry Warsaw]

On Tue, 2003-12-16 at 09:17, Gustavo Niemeyer wrote:

> I have done this many times, so let me try to describe at least one
> legitimate usage case. 
> 
> A couple of weeks ago I wrote a software which needs a third
> party package to work. OTOH, since it's a small package, I don't
> want to force the user to go after the package, even because I'd
> have to ensure that my code always work with the available version
> of that package.
> 
> Thanks to the relative module importing mechanism, solving that is no
> harder than copying the third party package into my own package
> namespace.
> 
> This idea could probably be expressed in some other way, hacking
> sys.path or whatever, but I belive this is a fairly common pattern,
> and I vote for introducing a scheme to differ between local/global
> importing which would not break the current flexibility.

I guess the difference is when you're writing an application vs. writing
a library.  When writing an application (like Zope or Mailman), we
already manipulate sys.path to include some non-standard locations. 
Incorporating a third-party package into the application then is a
simple matter of arranging to have its top level directory somewhere on
sys.path.  In Mailman, I do this with the email package, and various
codecs.

When writing a library, that's harder because you're imposing
requirements on the downstream consumer of your library.

As an application developer, I don't have much sympathy for relative
imports.  As a library developer, I can see the point.

-Barry