Andrea Fontana:
If I'm right, index should be a compile-time value.
Right. Because tuples in general don't contain N values of the same type (as in your case), so the compiler has to know statically the index to compute their position efficiently.
Further similar questions are better asked in D.learn.I also suggest to not mix tab and spaces to indent code, configure your editor to use only spaces or only tabs (4 spaces is the D standard).
Bye, bearophile
