Re: [CFT] patch to replace the regex code

On 25 Jun 2011 15:08, "Gabor Kovesdan" <gabor_at_freebsd.org> wrote:
>
> Hi Folks,
>
> you may know that in the Summer of Code programme I'm working on replacing
the old regex code with TRE, which is a BSD-licensed implementation. It
supports wide characters, is POSIX-compliant and has a good performance
compared to most of the open source implementations. Actually, I got mixed
results. With sed, in the cases that I tested, the performance was more or
less the same and in some few cases, TRE finished in half of the time. On
the other hand, with grep sometimes it was significantly slower than the
current regex code but grep has always been a complicated case.

Forgive me if I'm patronizing, but is there any surprise that a POSIX NFA
implementation is slower than grep's DFA?

Chris