[Python-Dev] Tweaking AST lineno and col_offset

Benjamin Peterson benjamin at python.org
Fri Aug 14 18:16:47 CEST 2009

2009/8/14 Frank Wierzbicki <fwierzbicki at gmail.com>:
> Hi all,
> Off and on I have been directly comparing Jython's AST with Python's
> AST and generally working towards making them as close to identical as
> possible.  There are a couple of places where I haven't "fixed" Jython
> because it looks to me like Jython has slightly better offsets.  One
> example:
> for a,b in c:
>    pass
> The Tuple node "a,b" ends up with a col_offset of 0 (the position of
> the "for") where Jython has the col_offset as 4 (the position of "a").
>  Jython's result is more consistent with other Tuple node col_offset
> results.
> I have a local patch that changes the CPython col_offset to match
> Jython's, but before I submit a patch I thought I'd ask here if there
> is support for this sort of change and if I should continue to find
> col_offset and lineno results that look fishy to me, or should I just
> change Jython's results to match (one way or another, things will be
> much easier for me to test if they match).

Yes, please submit it.

> Also, would this be a change that would be considered a backwards
> incompatibility?  In other words, would patches like this be allowed
> in 2.6/3.1 or only in 2.7/3.2.

While I don't see a problem in backporting it to maintence branches, I
would personally only apply it to the current development branches. It
doesn't seem to fix a "bug", just make a nice improvement.


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