...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
boost::proto::context::null_context — An evaluation context for proto::eval() that simply evaluates each child expression, doesn't combine the results at all, and returns void.
// In header: <boost/proto/context/null.hpp> struct null_context { template<typename Expr, typename ThisContext = null_context const> struct eval : proto::context::null_eval< Expr, ThisContext > { }; };