Gordon McMillan wrote:
[Jim Fulton]
Here's an example that I hope will be motivating:
Suppose Marc-Andre has a package mx with subpackages DateTime and stringtools. ... Zope has a notion of products which are *self contained* packages that are sub-packages of the Products package. So, suppose someone wants to write a NiftyDB product, which is a Zope product that provides access to an external database. Now the author of the NiftyDB product wants to use the mx package. The mx package is not a standard part of Zope, or of Python, so they simpley include it in the NiftyDB product directory.
This would motivate me to strangle the author of NiftyDB. He should say "This requires Marc-Andre's mx package", and put error handling on the import.
This is unacceptable. People should not have to hack a global namespace to get a local feature.
Otherwise I might end up with a gazillion separate copies of the mx package installed on my system and no way to clean it up.
Or you might not. In any case, the ability to have localized references should be there. Actually, Zope does provide a place to share packages that multiple products use. This involves putting shared packages in a sub-package of the 'Shared' package. For example, Digital Creations shared packages go in Shared.DC. Putting mx in Shared.ACME runs into the same problem. Although the product author can: import Shared.ACME.mx.DateTime the import of mx.stringtools in DateTime will still fail. Now, maybe ACME will hack mx to change the internal imports: import Shared.ACME.mx.stringutils but their hacks will get broken when we make Zope a package and Shared becomes a sub-package of Zope.
Your notion of "self contained packages" is flawed. Reducto ad adsurdum, it leads to downloading the OS with every app you install. (Crap, I hope I haven't given Sun any new ideas...).
I'm sorry, but relying on existing Python installations for commercial applications is just not practical. In fact, Zope binary distributions contain their own Python distributions because relying on preinstalled Python distributions is just way too much of a support burden and a hassle for out customers. 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.