[Python-Dev] lib2to3, need some light on the imports fixer

[Collin Winter]

On Fri, May 16, 2008 at 10:30 AM, Guilherme Polo <ggpolo at gmail.com> wrote:
> 2008/5/12 Collin Winter <collinw at gmail.com>:
>> On Mon, May 12, 2008 at 1:58 PM, Guilherme Polo <ggpolo at gmail.com> wrote:
>>> Hello,
>>>
>>>  Would someone tell me how can I add a new entry in the MAPPING dict in
>>>  the lib2to3/fixes/fix_imports.py that does the following:
>>>
>>>  "import A" gets fixed as "import C.D as A"
>>>
>>>  Right now it is fixing by doing "import C.D" and changing several
>>>  other lines in the code to use this new "C.D" name. I wanted to avoid
>>>  these changes if possible.
>>
>> I don't believe there's a way to do that, but adding support for it
>> should be fairly straight-forward. Assign the patch to me for review.
>>
>
> Is there something I could read get some 2to3 understanding ?

The README is a very shallow overview, but it needs to be beefed up to
talk about architecture. Honestly, the best way (currently) is to read
the existing fixers. Mea culpa.

> How do I construct patterns ?

find_pattern.py is the tool I wrote/use to find patterns. You give it
some Python code and it spits out the pattern for it. It's hard to
hand-construct patterns due to some optimizations done to eliminate
unneeded nodes (nodes with only a single child are eliminated, pulling
the child to its grandparent).