Gordon McMillan wrote:
[relative package imports] [JimF]
I'll second Marc-Andre here.
A significant headache occurs when you have a package that has sub-packages. Sub-packages need to be able to reference other sub-packages within the same package without knowing where the containing package is installed. [GvR] You never need to know where it is installed. When I said absolute package name I meant package name (e.g. zope.foo.bar.subpack) not filename. As Tim has argued, the ability to change the name of the toplevel here is a liability, not a feature.
In between. I can see relative packages as *one* way of handling certain problems. Consider:
zope.Win32 zope.Unix
with both of these having alternate implementations of subpackages foo and bar. Then for (the current) foo.a to get to (the current) bar.b, using a relative import seems a natural.
I wouldn't use relative imports for this.
This can, of course, be done in pure Python. So can doing things in zope.__init__.py that make the appropriate implementations of foo and bar appear to be zope.foo and zope.bar. On any criteria I can think of, this would be a superior solution. (*)
I agree. This is not a good motivating example for relative imports.
What I am against is further complicating the already over complicated built in import mechanism.
The current scheme doesn't seem all that complicated to me. I wouldn't be in favor of making it more complicated if there wasn't a good reason. I think that, in working on the Zope framework, I've found some pretty good reasons for relative imports.
(*) such as a zope.__init__.py that looks like this:
import sys if sys.platform[:3] == 'win': nm = __name__ + '.Win32' else: nm = __name__ + '.Unix' new = __import__(nm) sys.modules[__name__] = sys.modules[nm]
Right, this would be silly. This is not a good example. Jim -- Jim Fulton mailto:jim@digicool.com Python Powered! Technical Director (888) 344-4332 http://www.python.org Digital Creations http://www.digicool.com http://www.zope.org Under US Code Title 47, Sec.227(b)(1)(C), Sec.227(a)(2)(B) This email address may not be added to any commercial mail list with out my permission. Violation of my privacy with advertising or SPAM will result in a suit for a MINIMUM of $500 damages/incident, $1500 for repeats.