Description
If macro VERBOSE is defined during compiling the _sre module, debugging prints are added which help to debug internals of the regular expression engine. Unfortunately, it is a global option which affects evaluation of every regular expression. Since some Python code which uses regular expressions is executed at make, it makes building much more slower. Also, some regular expressions are used at the REPR startup, which adds a lot of noise. It makes this feature almost not usable.
The proposed PR allows to enable tracing on per-pattern basis. If macro VERBOSE == 1, tracing is only enabled for patterns compiled with the DEBUG flag. If VERBOSE == 2, tracing is always enabled, if VERBOSE == 0 it is always disabled.
This feature is for core developers only.