When specifying a dependencies and when asking for a package with easy_install, you can specify one or more specifiers. It's unclear what the rules are for combining specifiers. Imagine that I have a collection of eggs like: /home/jim/tmp/dist: used 92 available 41345796 -rw-rw-r-- 1 jim jim 671 Jun 19 17:43 demoneeded-1.0-py2.4.egg -rw-rw-r-- 1 jim jim 672 Jun 19 17:46 demoneeded-1.1-py2.4.egg -rw-rw-r-- 1 jim jim 673 Jun 19 17:46 demoneeded-1.2-py2.4.egg -rw-rw-r-- 1 jim jim 673 Jun 19 17:46 demoneeded-1.3-py2.4.egg -rw-rw-r-- 1 jim jim 673 Jun 19 17:46 demoneeded-1.4-py2.4.egg -rw-rw-r-- 1 jim jim 673 Jun 19 17:46 demoneeded-1.5-py2.4.egg -rw-rw-r-- 1 jim jim 673 Jun 19 17:46 demoneeded-1.6-py2.4.egg -rw-rw-r-- 1 jim jim 673 Jun 19 17:46 demoneeded-1.7-py2.4.egg -rw-rw-r-- 1 jim jim 673 Jun 19 17:46 demoneeded-1.8-py2.4.egg -rw-rw-r-- 1 jim jim 673 Jun 19 17:46 demoneeded-1.9-py2.4.egg Now, here are some examples of using the pkg_resources api to fetch a required distribution:
import pkg_resources e = pkg_resources.Environment(['tmp/dist']) ws = pkg_resources.WorkingSet()
ws.resolve([pkg_resources.Requirement.parse('demoneeded ==1.1, ==1.4')], e) [demoneeded 1.4 (/home/jim/tmp/dist/demoneeded-1.4-py2.4.egg)]
Here, the specifiers were or-ed. OK.
ws.resolve([pkg_resources.Requirement.parse('demoneeded >1.1, <1.6')], e) [demoneeded 1.5 (/home/jim/tmp/dist/demoneeded-1.5-py2.4.egg)]
Here they were and-ed. This makes sense, from a dwimy point of view. :) If they were or-ed, I'd expect to get 1.9.
ws.resolve([pkg_resources.Requirement.parse('demoneeded >1.1, <1.6, ==1.8')], e) [demoneeded 1.8 (/home/jim/tmp/dist/demoneeded-1.8-py2.4.egg)]
Hm, here the ==1.8 seems to have been or-ed with the result of anding >1.1 and <1.6.
ws.resolve([pkg_resources.Requirement.parse('demoneeded <1.1, >1.6')], e) [demoneeded 1.9 (/home/jim/tmp/dist/demoneeded-1.9-py2.4.egg)] ws.resolve([pkg_resources.Requirement.parse('demoneeded !=1.8, ==1.8')], e) [demoneeded 1.9 (/home/jim/tmp/dist/demoneeded-1.9-py2.4.egg)]
I really don't know what's going on with these. :) Are the rules for combining specifiers specified anywhere? Jim -- Jim Fulton mailto:jim@zope.com Python Powered! CTO (540) 361-1714 http://www.python.org Zope Corporation http://www.zope.com http://www.zope.org