[Python-ideas] Extending traceback to (optionally) format and show locals.

[Robert Collins]

On 27 November 2014 at 14:12, Andrew Barnert <abarnert at yahoo.com> wrote:
> On Nov 26, 2014, at 15:45, Robert Collins <robertc at robertcollins.net> wrote:

>> I'm sure there is code out there that depends on the quadruple nature
>> of extract_stack though, so I think we need to preserve that. Three
>> strategies occured to me; one is to have parallel functions, one
>> quadruple, one quintuple. A second one is to have the return value of
>> extract_stack be a quintuple when a new keyword parameter
>> include_locals is included. Lastly, and this is my preferred one, if
>> we return a tuple subclass with an attribute containing a dict with
>> the rendered data on the locals; this can be present but None, or even
>> just absent when extract_stack was not asked to include locals.
>
> There are lots of other cases in the stdlib where something is usable as a tuple of n fields or as a structseq/namedtuple of >n fields: stat results, struct_tm, etc. So, why not do the same thing here?

Because backwards compatibility. Moving to a namedtuple is fine -
changing the length of the tuple is a problem.

-Rob


-- 
Robert Collins <rbtcollins at hp.com>
Distinguished Technologist
HP Converged Cloud