Passing operator as a parameter

Question

I want to have a function that evaluates 2 bool vars (like a truth table)

for example:

since

T | F : T

then

myfunc(\'t\', \'f         


        

Answer 1

What you can do is define proxy operators that return specific types.

namespace detail {
    class or {
        bool operator()(bool a, bool b) {
            return a || b;
        }
    };
    class and {
        bool operator()(bool a, bool b) {
            return a && b;
        }
    };
    // etc
    class X {
        or operator||(X x) const { return or(); }
        and operator&&(X x) const { return and(); }
    };
};
const detail::X boolean;
template bool myfunc(bool a, bool b, T t) {
     return t(a, b);
}
// and/or
bool myfunc(bool a, bool b, std::function func) {
    return func(a, b);
}
// example
bool result = myfunc(a, b, boolean || boolean);

You can if desperate chain this effect using templates to pass complex logical expressions.

Also, the XOR operator is bitwise, not logical- although the difference is realistically nothing.

However, there's a reason that lambdas exist in C++0x and it's because this kind of thing flat out sucks in C++03.