sortOn: sorts range of aggregates by member name(s)

["Nordlöw" via Digitalmars-d]

On Wednesday, 5 November 2014 at 16:54:38 UTC, Marc Schütz wrote:
> My idea was something along these lines (untested):
>
>     template extractorFun(alias extractor) {
>         static if(is(typeof(extractor) : string)) {
>             auto ref extractorFun(T)(auto ref T a) {
>                 mixin("with(a) { return " ~ extractor ~ "; }");
>             }
>         } else {
>             alias extractorFun = extractor;
>         }
>     }
>
>     alias fn = extractorFun!extractor;
>     r.sort!((a, b) => (fn(a) < fn(b)));

Thanks, I'll use this!

Still, is it even possible to extend extractor to become variadic 
or do I have to write a number of explicit overloads

1: void sortBy(alias xtr, R)(R r)
2: void sortBy(alias xtrA, alias xtrB, R)(R r)
3: void sortBy(alias xtrA, alias xtrB, alias xtrC, R)(R r)
etc

?