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

Function template keep

boost::xpressive::keep — Create an independent sub-expression.

Synopsis

template<typename Xpr> unspecified keep(Xpr const & xpr);

Description

Turn off back-tracking for a sub-expression. Any branches or repeats within the sub-expression will match only one way, and no other alternatives are tried.

Parameters:

xpr

The sub-expression to modify.

Notes:

keep(xpr) is equivalent to the perl (?>...) extension.