Variadic grouping

[bearophile]

monarch_dodra:

> Select!(cond, 1, 2);// This doesn't compile

Time ago I asked for an improvement of Select:
https://github.com/D-Programming-Language/phobos/pull/1235

Maybe there is a way to allow that too:


template Select(bool condition, T...) if (T.length == 2) {
     static if (condition)
         enum Select = T[0];
     else
         enum Select = T[1];
}

void main() {
     enum x = Select!(true, 10, 20);// error
     static assert(x == 10);
     int a = 1;
     int b = 2;
     alias y = Select!(true, a, b);
     assert(y == 1);
     alias T = Select!(true, int, long);
     static assert(is(T == int));
}


How do you tell apart values from not values? :-)

Bye,
bearophile