Can't get expected strings

[Jonathan M Davis via Digitalmars-d-learn]

On Tuesday, July 18, 2017 13:49:11 helxi via Digitalmars-d-learn wrote:
> import std.stdio, std.datetime, std.conv, std.algorithm;
>
> void main()
> {
>      immutable DEADLINE = DateTime(2017, 7, 16, 23, 59,
> 59).to!SysTime;
>      immutable NOW = Clock.currTime;
>      immutable INTERVAL = (DEADLINE - NOW)
>                          .abs
>                          .to!string;
>                          //if I put .until("secs") here, it prints
> the full-type
>                          //immutable(Until!("a == b", string,
> string))("1 day, 23 hours, 47 minutes, 30 secs, 508 ms, 119 μs,
> and 6 hnsecs", "secs", yes, false)
>
>
>      writeln(INTERVAL);
>
>      //But I don't want these until("secs") below:
>      if (NOW > DEADLINE) writeln(INTERVAL.until("secs"), "seconds
> ago.");
>      //1 day, 23 hours, 48 minutes, 55 seconds ago.
>      else if (NOW < DEADLINE) writeln(INTERVAL.until("secs"),
> "seconds ahead.");
>      else writeln("Now.");
> }
>
> -----
>
>
> Why is to!string providing inconsistent string?

Because the output of Duration.toString strips any units that are 0. It's
intended to be human readable, not machine parseable. If you want a specific
format, I'd suggest that you grab the units on your own and create the
string that you want rather than trying to parse the result of toString.

If you want the entire Duration in seconds, then do something like

auto diff = Clock.currTime - deadline;
writefln("%s seconds ago", diff.total!"seconds");

whereas if you want to split out the units so that you get the seconds
portion beyond the minute, then you'd do something like

auto diff = Clock.currTime - deadline;
writefln("%s seconds ago", diff.split!("minutes", "seconds").seconds);

http://dlang.org/phobos/core_time.html#.Duration.total
http://dlang.org/phobos/core_time.html#.Duration.split

- Jonathan M Davis