Planned regexp change - comments & legal issues.

["Harvey J. Stein" <hjstein@bfr.co.il>]

I talked to Aharon Robbins (gawk maintainer) about gawk's regexp
implemetation vs libc vs others (rx & Henry Spencer's code).  He
basically said:
 - don't use rx,
 - gawk uses GNU regex & dfa from grep.
 - The main advantage is the ability to turn on & off "particular
   syntax features".
 - The main disadvantage is that it's slow & occasionally very flakey
   & very hard to fix if bugs show up.
 - Spencer's stuff is very well-written & very fast.
 - If it wasn't for inertia & the fact that it's less flexible, then
   he'd switch to Spencer's code.

Also, I discovered that STk uses TCL's regexp code which is Spencer's
code & it seems to be faster than gawk's code in the stupid test that
I've been doing.

Upshot - It'd be a better idea technically to use Spencer's code than
gawk's code.

Question - Is it a problem using Spencer's code, given that it's not
GPLed?  I'd assume yes from previous discussions on the list, but I'd
assume no from Robbins' comments that he'd switch to it for gawk if it
wasn't for flexibility & inertia (i.e. - reading btw the lines says
that the licensing isn't an issue).

-- 
Harvey J. Stein
BFM Financial Research
hjstein@bfr.co.il