I have sort of a dumb question about this. What would be the motivation for using Xpressive if its not faster than regex? Putting it another way, I would have thought that Xpressive would be faster with the cost of more code being instantiated every time it's invoked. What else is going on here? Another question: How would using expressive be different than using spirit with a regular expression grammar? I have no purpose for asking other than idle curiosity. Robert Ramey Eric Niebler wrote:
John Maddock wrote:
Eric Niebler wrote:
Boost.regex: 6.859 Boost.xpressive (dynamic): 3.02 Boost.xpressive (static): 2.912
With boost.regex, I couldn't use an independent subexpression because it disables the optimization. That accounts for the difference.
I've just extended the optimization to more cases in Boost.Regex (SVN Trunk), so the two libraries should be back on a par now performance wise (I hope!)
Confirmed, nice work. <tips hat>