...one of the most highly
regarded and expertly designed C++ library projects in the
world. — Herb Sutter and Andrei
// In header: <boost/yap/algorithm.hpp> template<typename Expr> auto make_expression_function(Expr && expr);
Returns a callable object that expr has been forwarded into. This is useful for using expressions as function objects.
Lvalue expressions are stored in the result by reference; rvalue expressions are moved into the result.