Do not use cmp for sorting lists and dictionaries

[Garth Wells]

cmp has been removed from Python 3. To be ready for the change, UFL should not use cmp, but should implement __lt__ and __eq__.

[Martin Sandve Alnæs (martinal)]

Fixed. (__cmp__ was only implemented in graph.py, which is only used by sfc afaik, and will be removed at some point in the future since uflacs has does these things better).

[Martin Sandve Alnæs (martinal)]

I only fixed the __cmp__ use, working on other cmp() uses. Not much.

[Garth Wells (garth-wells)]

Once we get Python components Python 3 compatible, we should add
something to the buildbots to make sure we don't undo the Python 3
compatibility.

Garth

On Wed, Jan 2, 2013 at 10:04 AM, Martin Sandve Alnæs
<email address hidden> wrote:
> I only fixed the __cmp__ use, working on other cmp() uses. Not much.
>
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[Martin Sandve Alnæs (martinal)]

What's the minimum python version we need to support? The buildbots have 2.6, which does not have the functools.cmp_to_key helper function to ease the trasition to the removal of cmp.

[Martin Sandve Alnæs (martinal)]

Should be fixed now, but this is a bit hard to know... I bet there are other latent issues in the python 3 changes as well. Also, these changes will probably reduce performance somewhat as I had to construct a proxy key object for each comparison, which happens quite often.