RE: Time library discussion (reprise)

On Tue, 11 Nov 2003 12:44:59 -0000 "Simon Marlow" wrote:

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This has been demonstrated - recently by Juanma Barranquero's library posted to the Haskell list,

I think you're referring to Stefan Karrmann's library. I just did a couple comments about it.

Oops! My apologies.

IMHO, Haskell should have a simple module which allowed to manipulate dates and times in UTC (and convert to/from localtimes, and perhaps MJD/JD), and, as an extension, a TAI module for the (probably very few) people who needs that kind of precision.

Let's talk in concrete terms. Could you propose an API for what you have in mind for the basic UTC functionality? Presumably, without TAI support, the library will be unable to do accurate calendar calculations at the second level (i.e. "add S seconds to time T"), although it will be able to do larger scale calendar calculations (i.e. adding days, months, etc.). Or maybe you provide the second-level calculations but document that they don't take into account leap seconds?

I know that I've been programming quite a few years and I've never needed to know TAI times, nor ignoring the leap seconds have been a problem. And, till very recently, I was working for a VoIP carrier, so you can bet we manipulated dates, times and durations *constantly*. I'm not saying there aren't problem domains where that level of precision is required. Just they're not that common, I think.

Ok, it's useful to have someone with experience of actually using this stuff for Real Work. As always, I'm happy to go along with a concensus if one can be reached. Cheers, Simon