// In header: <boost/yap/user_macros.hpp> BOOST_YAP_USER_CALL_OPERATOR(expr_template)
Defines operator overloads for the call operator taking any number of parameters ("operator()") that each produce an expression instantiated from the expr_template expression template. One overload is defined for each of the qualifiers
&&. For the lvalue reference overloads,
*this is captured by reference into the resulting expression. For the rvalue reference overload,
*this is moved into the resulting expression.
The u parameters to each of the defined overloads may be any type, including an expression. Each non-expression is wrapped in a terminal expression.