c++ - How to replace macro with a template function? -

i have macro:

#define two_cmd( c1, c2 ) { const long r1=c1; if ( r1 ) return r1; return c2; } 

and using:

long myclass::somefunc( long ) {     //...     if ( )         two_cmd( func<int>(a), func<void>() );     else         two_cmd( func<double>(), func<std::string>(a) );     //... } 

func template member functions. key requirement keep readability of code!

i guess there variant template member function have pointer member functions arguments:

return two_cmd( func<int>, a, func<void> ); 

but syntax not clear.

first thing first: hiding return statement inside of macro evil. when 1 looks @ function, not @ clear calls two_cmd cause function return.

the easiest way pass callable objects function template , have return result:

template <typename r, typename f, typename g> r evaluate(const f& f, const g& g) {     r x = f();     return x ? x : g(); } 

used as:

return evaluate<long>(     std::bind(&myclass::func<int>, this, a),      std::bind(&myclass::func<void>, this));  return evaluate<long>(     std::bind(&myclass::func<double>, this),      std::bind(&myclass::func<std::string>, this, a)); 

if compiler , standard library not support c++0x or c++ tr1 bind, there implementation in boost identical.

(i've named function evaluate because can't think of name function.)