This is similar to efforts (Feb 2010) but using ragel
(https://en.wikipedia.org/wiki/Ragel) instead of the now defunct
coco/r. The modified commit message from 2010:
ENH: add C++-based wmkdepend parser (uses ragel grammar).
- This avoids dependency on lex/flex and provides better encapsulation
for buffer switching. As a result, the maximum number of open files
only corresponds to the include depth.
--
Note that the flex source and rules are still available, but are not
deactivate (see wmake/rules/General/transform)
