>> What it does is that it injects the classes defined in this particular >> module to the other modules. First problem: 2to3 tool doesn't convert >> this correctly, I had to manually conver this >> to: > > Would you file a bug report for the 2to3 problem, please? That should be > fixed.
I will. There are a lot more import conversions problem like this one. >> However, this works in python2.4, 2.5 and 2.6. Notice, that "from . >> import mul as _" worked in power.py, but failed in add.py 3 lines >> below. This is weird, isn't it? > > Actually, if you use the relative imports with 2.6, it fails like 3.0. > 3.0 is just being stricter. > >> >> So my questions are: >> >> * is our "hack" supported at all? If not, how would you suggest us to >> handle cyclic imports? Basically, we want Add and Mul classes to be >> defined in separate modules, however the methods of both classes need >> access to the other --- so the only other option that I can see is to >> locally import the other module in each method, which is slow and not >> so clean. Another option is to import the other class to the module at >> runtime using some dynamic features of Python. > > First, I suggest instead of using sibling imports in your packages, > you should convert to all relative imports or all absolute imports. > (ie. from sympy.core import something) The problem is that we still need to support python2.4, so the only option seems to be absolute imports. I think from the major distributions, only Debian and Gentoo still use 2.4 in their stable versions, but everyone now uses 2.5 in their unstable versions, so I guess we need to support 2.4 for at least one more year or two. > > Instead of inserting Mul into the namespace of different modules, you > do something like: > > from .mul import Mul > > at the bottom of files that use the cyclic import. Ok, I'll try to fix it this way. > >> >> * if it is supposed to work, is this a bug in python3.0? > > No, Python 3.0 is just being stricter. :) You may want to test this > out by using "from __future__ import absolute_import". Thanks for the info. So I'll first convert the imports, then run it through 2to3 again and report all problems again. I noticed, that no imports from sympy/__init__.py and all the other __init__py files were converted and they fail with python3.0. I must admit, that because I was still using python2.4, I must first learn how it works (e.g. naively adding the dot like "from .functions import *" sometimes fail) and then report back when I understand it more. Ondrej _______________________________________________ Python-3000 mailing list Python-3000@python.org http://mail.python.org/mailman/listinfo/python-3000 Unsubscribe: http://mail.python.org/mailman/options/python-3000/archive%40mail-archive.com
