python-aware wdiff?

[Terry Reedy]

On 7/14/2014 11:12 AM, Roy Smith wrote:
> Does anybody know of a wdiff-like tool
> (http://www.gnu.org/software/wdiff/) which is aware of python syntax and
> can show token changes instead of word changes.  Wdiff is can turn
>
> -    if not metar.is
> <http://metar.is>_in_temp_range_f(situation.weather.low_temperature,
> situation.weather.high_temperature):
> +    if not info.is
> <http://info.is>_in_temp_range_f(situation.weather.low_temperature,
> situation.weather.high_temperature):
>
> into
>
>      if not
> [-metar.is_in_temp_range_f(situation.weather.low_temperature,-]
> {+info.is_in_temp_range_f(situation.weather.low_temperature,+}
> situation.weather.high_temperature):
>
> but what I really want is:
>
>      if not
> [-metar-]{+info+}.is_in_temp_range_f(situation.weather.low_temperature,
> situation.weather.high_temperature):
>
> which makes it more obvious that the change is just the one token.  Does
> such a tool exist?

The under-known difflib.differ shows within line differences.
Your example would look like:

-    if not metar.is_in_temp_range_f(...):
?           ^^^^^
+    if not info.is_in_temp_range_f
?           ^^^^

Deletions and insertions are indicated with '-' and '+'.
I use this routinely, when backporting patches, in a script that differs 
the 2.7 and 3.4 versions of repository files.

-- 
Terry Jan Reedy