Boost C++ Libraries

“...one of the most highly regarded and expertly designed C++ library projects in the world.” — Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

Global alpha

boost::xpressive::alpha — Matches an alphabetic character.

unspecified alpha;

The regex traits are used to determine which characters are alphabetic. To match any character that is not alphabetic, use ~alpha.