[Python-Dev] Re: Christmas Wishlist (original) (raw)

Barry Warsaw barry at python.org
Wed Dec 17 21:28:30 EST 2003

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

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