What to use instead of array.join if RHS is not a range?

[jerro]

> won't. You seem to be looking for a function which will insert 
> an element
> between every element in a range rather than one that joins 
> ranges, and I'm
> not aware of any function in Phobos which will do that. There 
> may be a way to
> get one to do what you want, but I can't think of how at the 
> moment.

roundRobin can be used for that. I think this is suposed to work:

auto r = roundRobin(arr, repeat(s).take(arr.length - 1));

This currently gives this error:

  Error: template instance 
std.range.roundRobin!(S[],Take!(Repeat!(S))) error instantiating

I think this is due to the fact that roundRobin.front has 
multiple return statements, some of which return an lvalue and 
some of which return an rvalue when instantiated with one range 
with rvalue elements and one with lvalue elements. The return 
type of roundRobin is auto ref and it seems that this becomes ref 
in this case. Because I don't know exactly how auto ref is 
supposed to work, I don't know whether this is a bug in DMD or in 
roundRobin.front.

This works:

auto r = roundRobin(arr, repeat(s).take(arr.length - 1).array);

And so does this:

auto r2 = roundRobin(arr.map!"a", repeat(s).take(arr.length - 1));