[phobos] Why TimeOfDay Doesn't have milliseconds property?

[Jonathan M Davis via phobos]

On Sunday, April 19, 2015 22:40:27 Muhammad Adel via phobos wrote:
> Hi
>
> Is there a reason for the TimeOfDay struct, and in return DateTime struct
> to not hold the milliseconds of a given time?

Because TimeOfDay, Date, and DateTime are intended for calendar-based
operations. Milliseconds is far more precision than is needed for that, and
including it would just make those data structures larger for little
benefit.

Anything relating to the system's clock should use SysTime, which has
hecto-nanosecond precision (100 ns). It's what Clock.currTime() returns and
what most programs should be using. If you're not doing a bunch of
calendar-based operations (like a calendar app would be doing), I would
expect the primary use case of TimeOfDay, Date, and SysTime would be to get
the various units of time from a SysTime efficiently rather than having to
redo the calculations over and over again as would occur if you asked for
them each indivdually from a SysTime.

Maybe TimeOfDay should have more precise units, but in general, if you're
asking why it doesn't have them, you're probably using the wrong type
anyway and should be using SysTime.

Also, questions like this are better asked in the Learn newsgroup, not
Phobos. Phobos is intended for discussions between the Phobos developers and
for those who wish to receive the commit messages for Phobos (and mostly
just the latter now that we use github). There is very little posting to
the Phobos list by humans these days.

- Jonathan M Davis