How do I specify a variadic template constraint on all the whole tuple?

[Andrej Mitrovic]

On Thursday, 18 July 2013 at 13:18:29 UTC, Atila Neves wrote:
> bool func(SYMBOLS...)() if(!is(typeof(SYMBOLS[0]) == string)) {
> }
> and
>
> bool func(STRINGS...)() if(is(typeof(STRINGS[0]) == string)) {
> }

Here you go:

-----
import std.string;
import std.traits;
import std.typetuple;
import std.functional;

bool func(Symbols...)(Symbols symbols)
     if (!anySatisfy!(isSomeString, Symbols))
{
     return true;
}

bool func(Strings...)(Strings strings)
     if (allSatisfy!(isSomeString, Strings))
{
     return true;
}

void main()
{
     func("1", "2");
     func(1, 2);
     static assert(!__traits(compiles, func(1, "2")));
}
-----

And remember you have to actually list the runtime arguments 
after the type arguments (e.g. 'Strings strings'), otherwise the 
template won't match.