On 5/12/22 12:51, ag0aep6g wrote:
>> auto iota(B, E, S)(B begin, E end, S step)
> [...]
>> {
>> static struct Result
>> {
>> B current;
> [...]
>> void popFront()
>> {
> [...]
>> current += step;
>> }
>> }
> [...]
>> }
>
> Mark iota's `begin` parameter as const. Then you don't need the cast,
> because `B` will be mutable.
Cool trick! Like this:
auto iota(B, E, S)(const(B) begin, E end, S step)
{
// ...
}
It works with non-const values as well. So apparently it makes the
function parameter const(B) and deduces B to be the non-const version of
that, which always produces the non-const version.
And I've been thinking 'iota' may not be as suitable as I thought at
first. I like the following even more:
auto r0 = st
.by(Duration(2))
.take(5);
auto r1 = st
.by(Duration(2))
.until(en);
A family of 'by' ovenloads can be defined or it can be templatized to be
used as 'by!Duration(2)' etc.:
auto by(DateTime dt, Duration dur) {
struct Result {
DateTime front;
Duration dur;
enum empty = false;
void popFront() { front += dur; }
}
return Result(dt, dur);
}
Just works. But one may want to provide an accessor for front().
Ali
