On Wednesday, 17 August 2016 at 19:38:22 UTC, Engine Machine wrote:
> Well, the is does work and that probably is the best solution. I don't mind the extra type at this point. Of course, a library solution for this type of stuff would be nice. I'd rather not have to even use a type but rather use arrays:
> [a,b,[c,d]].

Maybe you can use Tuple from std.typecons, instead of custom structs, that group the arguments.

Ex:

alias seqWithSubSeq = AliasSeq!(a, b, Tuple!(c, d))

http://dlang.org/phobos/std_typecons.html#.Tuple