Re: Another RFC: regex in libiberty

Jim Blandy
2001-06-12T06:48:00Z

Jim Blandy <jimb@cygnus.com> writes:
> To generate every possible match, you have to choose every possible
> way to divide up those twenty a's amongst six .* patterns. I think
> this is 20 choose 5, or 1.9 million, matches you have to try. In
> general, I think the time to match POSIXly can increase exponentially
> in the length of your regexp, given a long enough data string.

20 choose 5 is, of course, only 15504, not 1.9 million. Oops.