On Thursday, February 13, 2014 23:37:13 Timothee Cour wrote:
> Is there a function to do this?
> If not and I/someone writes it, is there interest to add it to std.datetime?
> 
> Duration t = ...;
> t.to!string => 5 secs, 889 ms, and 811 μs
> t.round.to!string    => 5 secs
> 
> t=...;
> t.to!string => 889 ms, and 811 μs
> t.round.to!string    => 889 secs
> 
> Use case: shorter logs.

There is no function for that, and no one's ever asked for anything like it, so I don't know how worthwhile it is to add. However, one possible implementation would be

auto roundToLargest(Duration d)
{
    foreach(units; TypeTuple!("weeks", "days", "hours", "minutes",
                              "seconds", "msecs", "usecs"))
    {
        immutable value = d.total!units();
        if(value != 0)
            return dur!units(value);
    }

    return d;
}

- Jonathan M Davis

thanks!


On Fri, Feb 14, 2014 at 2:14 PM, Jonathan M Davis <jmdavisProg@gmx.com>wrote:

> On Thursday, February 13, 2014 23:37:13 Timothee Cour wrote:
> > Is there a function to do this?
> > If not and I/someone writes it, is there interest to add it to
> std.datetime?
> >
> > Duration t = ...;
> > t.to!string => 5 secs, 889 ms, and 811 μs
> > t.round.to!string    => 5 secs
> >
> > t=...;
> > t.to!string => 889 ms, and 811 μs
> > t.round.to!string    => 889 secs
> >
> > Use case: shorter logs.
>
> There is no function for that, and no one's ever asked for anything like
> it,
> so I don't know how worthwhile it is to add. However, one possible
> implementation would be
>
> auto roundToLargest(Duration d)
> {
>     foreach(units; TypeTuple!("weeks", "days", "hours", "minutes",
>                               "seconds", "msecs", "usecs"))
>     {
>         immutable value = d.total!units();
>         if(value != 0)
>             return dur!units(value);
>     }
>
>     return d;
> }
>
> - Jonathan M Davis
>
>

On Fri, 14 Feb 2014 17:14:03 -0500, Jonathan M Davis <jmdavisProg@gmx.com> wrote:

> On Thursday, February 13, 2014 23:37:13 Timothee Cour wrote:
>> Is there a function to do this?
>> If not and I/someone writes it, is there interest to add it to std.datetime?
>>
>> Duration t = ...;
>> t.to!string => 5 secs, 889 ms, and 811 μs
>> t.round.to!string    => 5 secs
>>
>> t=...;
>> t.to!string => 889 ms, and 811 μs
>> t.round.to!string    => 889 secs
>>
>> Use case: shorter logs.
>
> There is no function for that, and no one's ever asked for anything like it,
> so I don't know how worthwhile it is to add. However, one possible
> implementation would be
>
> auto roundToLargest(Duration d)
> {
>     foreach(units; TypeTuple!("weeks", "days", "hours", "minutes",
>                               "seconds", "msecs", "usecs"))
>     {
>         immutable value = d.total!units();
>         if(value != 0)
>             return dur!units(value);
>     }
>
>     return d;
> }

You are doing the calculation for every test.

Better:
if(d >= dur!units(1))
   ...

Now, I think that the dur!units(1) should be statically determined, but if not, I think you could make it statically determined via enum.

-Steve

On Saturday, February 15, 2014 22:13:07 Steven Schveighoffer wrote:
> On Fri, 14 Feb 2014 17:14:03 -0500, Jonathan M Davis <jmdavisProg@gmx.com>
> 
> wrote:
> > On Thursday, February 13, 2014 23:37:13 Timothee Cour wrote:
> >> Is there a function to do this?
> >> If not and I/someone writes it, is there interest to add it to
> >> std.datetime?
> >> 
> >> Duration t = ...;
> >> t.to!string => 5 secs, 889 ms, and 811 μs
> >> t.round.to!string    => 5 secs
> >> 
> >> t=...;
> >> t.to!string => 889 ms, and 811 μs
> >> t.round.to!string    => 889 secs
> >> 
> >> Use case: shorter logs.
> > 
> > There is no function for that, and no one's ever asked for anything like
> > it,
> > so I don't know how worthwhile it is to add. However, one possible
> > implementation would be
> > 
> > auto roundToLargest(Duration d)
> > {
> > 
> >     foreach(units; TypeTuple!("weeks", "days", "hours", "minutes",
> >                               "seconds", "msecs", "usecs"))
> > 
> >     {
> > 
> >         immutable value = d.total!units();
> >         if(value != 0)
> > 
> >             return dur!units(value);
> > 
> >     }
> > 
> >     return d;
> > 
> > }
> 
> You are doing the calculation for every test.
> 
> Better:
> if(d >= dur!units(1))
>     ...

Yeah. That would be better.

> Now, I think that the dur!units(1) should be statically determined, but if not, I think you could make it statically determined via enum.

It'll only be statically determined if it's in a context that requires it. Unless something has changed recently, the compiler never tries to do CTFE if it doesn't have to. So, you'd need to use an enum to force it.

- Jonathan M Davis