On Wed, Nov 16, 2011 at 6:44 PM, Alexandru Ciobanu <a...@rogue-research.com> wrote:
> As it can be seen re2 and the standard regex.h are orders of magnitude > faster in executing this particular regular expression. > The difference between PCRE and re2 is also confirmed by this study: > http://swtch.com/~rsc/regexp/regexp3.html re2 does not implement some important PCRE features, such as backreferences, lookahead, lookbehind, recursion, etc: http://en.wikipedia.org/wiki/Comparison_of_regular_expression_engines http://developer.qt.nokia.com/wiki/Regexp_engine_in_Qt5 This is the reason Qt5 has discarded re2 to replace QRegExp and is considering adding UTF-16 support in PCRE. > CONCLUSTION: > - PCRE is not fast enough Yet this is the syntax and features that most developers would expect to find. > QUESTION: > - is there a reason we shouldn't use the standard regex.h? In addition to not implementing PCRE (which is what anyone would expect to find in a regexp engine these days), regex.h is not available in MSVC. MinGW does provide an implementation on Windows, though. There are two other regexp implementations Qt has considered: - Boost::Regex. Discarded because Boost does not keep ABI compatibility, which is important for Qt (but I'd say it's not for CMake) - C++11. Not possible if support for old compilers is required. Alex, have you tried those two? -- Pau Garcia i Quiles http://www.elpauer.org (Due to my workload, I may need 10 days to answer) -- Powered by www.kitware.com Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Follow this link to subscribe/unsubscribe: http://public.kitware.com/cgi-bin/mailman/listinfo/cmake-developers
