[Bf-committers] (re) proposal for pep8 for blender scripts

[Campbell Barton]

While at BConf I met with Stani (SPE, Phatch author) and Theo (PySlate
author), One thing that came up was how we don't have (any?) python
developers,
in the sense that active developers who write python scripts have
learnt from looking at other scripts in blender (myself), or C
developers who also write some python.

Who is/isn't a python developer is a bit vague, but I always get
really negative responses in #python whenever I show them our code,
and blender somehow has a very bad reputation there.

Stani and I went over the existing python scripts and API to see how
it could better conform to the 'python way', he found a few things
that are easy to fix, (eg. using __somevar__ when we shouldn't, maybe
follow how django defines fields (rna props)).

What interested me most was how we could use PyLint, PyFlages and
pythons pep8 checker to ensure consistent style.
we ran some tests on blenders code which showed many mixed
tabs/spaces, interestingly some bugs too (vars used before defined).

http://www.python.org/dev/peps/pep-0008/

I already wrote a mail suggesting pep8 which wasn't widely accepted
but now I'm more convinced then before that this is a worthwhile
change.
(reference old mail
http://lists.blender.org/pipermail/bf-taskforce25/2009-May/000827.html)

One exception I think we should make is the 80 width line.
Screen size is given as a reason for this however blender is graphics
software and I think its fair to assume people are not developing
blender on tiny screens,
pythons tools can be configured not to check for this.

Reasons to switch...
1) pep8 is strongly encouraged by (official) python
2) people who learn python in blender can transfer better to other projects
3) python developers have an easier time working on blenders code.
4) We get to use pythons tools for checking consistency. (and even finding bugs)

To me the reasons NOT to switch are just lazy
1) have to configure editor to use spaces
2) takes some effort to convert

While on its own style isn't so important to me I think this is one
way that we can improve blender/python.

With Phatch this change was made by converting files one by one,
commenting each as conforming, so as not to try fix all errors at
once.
Then changes to these scripts can be maintained by validated and corrected.
To me this seems a sensible way to get this done.

-- 
- Campbell