A Discussion of Tuple Syntax

[bearophile]

Meta:

> It *could* be an underscore; the only thing is that the 
> underscore is a valid variable name, so the above expression 
> would actually be binding two variables, which might surprise 
> someone who was expecting otherwise. I don't really care all 
> that much, but it's something to think about.

You can't define a variable more than once in a scope, so this 
can't be valid:

void main() {
     auto t1 = #(5, "hello", 1.5);
     auto (_,  _, x) = t1;
     auto (_, gr, _) = t1;
}


While ? defines nothing, so this is OK:

void main() {
     auto t1 = #(5, "hello", 1.5);
     auto (?,  ?, x) = t1;
     auto (?, gr, ?) = t1;
}

Bye,
bearophile