gigasecond: use times (not dates) for inputs and outputs

[kytrinyx]

A duration of a gigasecond should be measured in seconds, not
days.

The gigasecond problem has been implemented in a number of languages,
and this issue has been generated for each of these language tracks.
This may already be fixed in this track, if so, please make a note of it
and close the issue.

There has been some discussion about whether or not gigaseconds should
take daylight savings time into account, and the conclusion was "no", since
not all locations observe daylight savings time.

[canweriotnow]

👍 for no DST; in fact, it would make the most sense to default everything to UTC.

One thing that I was wondering about exercism 'opinion' on - 3rd party libs. I see it as more of a challenge to disallow/discourage them, but what you're describing is much simpler (in 'pure' Clojure) with the clj-time lib than relying on java.util.Date and Java interop. But I'll put investigating this on my TODO list, DateTime code is my area of dubious expertise 😒

[kytrinyx]

In terms of Date I'm not really sure what to choose. Mostly I think we've just gone with standard/core functionality around generic date/time, whereas for things like prime numbers, leap years, and a couple of other things, we discourage (or disable) existing behavior.

[canweriotnow]

Nobody wants to use the existing behaviour for leap years... have you used java.util.GregorianCalendar? 😨

[kytrinyx]

No, actually :) I haven't!

[canweriotnow]

Lucky :)

[yurrriq]

It's not so bad haha. doto to the rescue. Also date/time handling is greatly improved in the JDK 1.8.

[yurrriq]

Also 1.7 is deprecated by Oracle. I can track down a link of proof if needed. Maybe we should require users to use 1.8. Thoughts?

[haus]

If we required 1.8, we could use LocalDateTime here, which would be nice.

Here is the oracle doc on java support http://www.oracle.com/technetwork/java/eol-135779.html (Java 7 support ended in April 2015).

[kotp]

My opinion with this is that asking for a date leaves some doubt as to when to start counting seconds... do you start at the beginning of the day or the end of the day? If I ask for a birthday you will not likely give me down to the seconds. The wording of "moment" leaves this exercise a bit open, the discussion about what to ask for in the argument list, the fact there is ambiguity when asking for a date, rather than a time, the fact that at least in the Ruby track, the most common solutions allows to even just provide 12.76 as a number of seconds and a "gigasecond" is not-surprisingly added to that number of seconds, in the most generic of sense.

Leaving it open provides for a number of solutions and room to discuss a lot of things for the exercise. Not asking for time or date allows for this.

Of course, you also have the potential for time zone complications. :)