Dates API: Allow n * Dates.Minute etc.

[Tetralux]

In reference to issue #13763, it occurred to me that it might be worth considering borrowing a couple of other features from Go which also relate to select statements. Namely:

1. Add something like after(::Dates.Period) which yields a Channel which provides a single value after that period of time. Already exists in the form of Timers.
2. Add the ability to multiply an Integer or AbstractFloat by a subtype of Dates.Period to get the number of seconds that duration represents, as a number or a TimePeriod object.
   e.g: 4 * Dates.Second => 4; 1.255 * Dates.Minute => 75.3

You would then, for instance, be able to do things like this: sleep(5 * Dates.Minute)

[malmaud]

I'm not clear on what 1) and 2) are doing that the current Timer function and Dates function aren't already doing.

[Tetralux]

@malmaud
I concede that the Timer type does already implement the functionality I suggest. My mistake.

RE 2) however, it's a question of readability, and simplicity.
Consider: Timer(4.5 * Dates.Minutes) vs. Timer(Dates.Minutes(4) + Dates.Second(30))
One is cleaner, and clearer, than the other, and the brackets could be considered noise in code that already has a lot of brackets.
The closest thing we have to this at the moment is 4 * Dates.Minute(1), which floats cannot be used with.

Of course, if you wish to expressing an exact number of minutes and seconds is important, then 4.5 is not as ideal but in those situations you would still be able to use Dates.Minute(4) + Dates.Second(30).

It's really more of a style thing, than functionality.

[malmaud]

Alright, maybe you could change the title of this issue to reflect that it's now about the Dates API.
I agree that something like that would be neat.
cc @quinnj who maintains the Dates code.

[KristofferC]

Closing as dup of #10449