What's wrong with my usage of std.algorithm.map in this code example?

[ag0aep6g via Digitalmars-d-learn]

On 05/25/2016 03:27 PM, Chris wrote:
> Why can the tuple be iterated with foreach, as in my quick fix, and
> indexed with tuple[0..], but is not accepted as a range? What are the
> differences?

popFront doesn't make sense with a tuple (aka expression list). When you 
remove the first element of a tuple, you get another tuple of a 
different type, but popFront can't change the type of the range.

In code:

----
void main()
{
     import std.meta: AliasSeq;
     AliasSeq!(int, int, int) tuple = AliasSeq!(1, 2, 3);
     tuple.popFront(); /* How would this be implemented? Would have to 
change tuple's type to AliasSeq!(int, int). */
}
----

> Is there a way to rangify a tuple?

std.range.only:

----
void main()
{
     import std.meta: AliasSeq;
     import std.range: only;
     AliasSeq!(int, int, int) tuple = AliasSeq!(1, 2, 3);
     auto range = only(tuple);
     range.popFront(); /* ok */
}
----