On Wednesday, 25 May 2016 at 14:32:11 UTC, ag0aep6g wrote:
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 */
}
----
I see. Maybe it would be worth adding a wrapper to typecons.Tuple
or std.range that helps to rangify tuples. I cannot think of any
use case right now. I never needed this and in the example that
started this thread, it would keep the function from converting
mixed tuples (cf. my example above).
