On Mon, Jan 28, 2013 at 08:50:56AM -0500, Richard Hipp wrote: > The regular expression matching in > www.fossil-scm.org/fossil/artifact/c8fb75a1615f is also lightweight and it > supports | and it is usually as fast or faster than grep in my tests > (though there are some cases for which grep is faster). The regexp.c in > fossil uses a NFA which gives worst case performance of O(NM) where N is > the size of the input text to be matched and M is the size of the regular > expression. Perl regular expressions and lua-regexp.c take exponential > time for some (admittedly obscure) regular expressions. On the other hand, > Perl regular expressions are more complete, and both Lua and Perl allow you > to do substitutions, which the regexp.c file in Fossil does not.
The Lua implementation starts to perform very badly as soon as you have wild cards at the beginning of the pattern. Those aren't even obscure... Joerg _______________________________________________ fossil-users mailing list fossil-users@lists.fossil-scm.org http://lists.fossil-scm.org:8080/cgi-bin/mailman/listinfo/fossil-users
