...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
boost::parser::if_
// In header: <boost/parser/parser.hpp> template<typename Predicate> constexpr auto if_(Predicate pred);
Returns an if_directive
that fails if the given predicate pred
is false
, and otherwise, applies another parser. For instance, in if_(pred)[p]
, p
is only applied if pred
is true.