John Maddock wrote:
there is one complicated expression that xpressive didn't compile, but which Boost.Regex and PCRE did handle OK.
I've tracked this down. xpressive is rejecting this regex because it is invalid according to the TR1 spec. It begins: const char* highlight_expression = "(^[ \t]*#(?:[^\\\\\\n]|" "\\\\[^\\n_[:punct:][:alnum:]]*[\\n[:punct:][:word:]])*)|" ----------------------------------------------^^^^^^^^ The problem is [:word:]. "word" is not a valid char-class-name, according to the TR1 spec: "Expressions of the form [[:class-name:]] are recognized, and are sensitive to the locale encapsulated by the traits class. The range of values for class-name is determined by the traits class, but at least the following names are recognized: alnum, alpha, blank, cntrl, digit, graph, lower, print, punct, space, upper, xdigit." If you change your regex to use "\\w" instead of "[:word:]", xpressive compiles it fine. (xpressive sure could give a better error in this case, though. :-/) -- Eric Niebler Boost Consulting www.boost-consulting.com