[r6rs-discuss] [Scheme-reports] Date and time arithmetic library proposal for R7RS large Scheme

[Per Bothner]

On 11/27/2010 06:17 PM, Ray Dillinger wrote:
> If we treat the cesium standard as the preferred unit for seconds,
> then we are true to the SI standard for seconds, but there are two
> downsides.  ... The major one is that
> we cannot get the local time corresponding to a numbered second
> more than a year in the future, nor the numbered second corresponding
> to a specified date and time more than a year in the future.

I can imagine wanting seconds to have a fixed length, and wanting to
correct for leap-seconds when dealing with times in the past or immediate
future (e.g. when setting a timer to record a program tomorrow).

I can't imagine needing second-level precision for times more than a
year in the future.

E.g. if I set an alarm to go off 2 years in the future, I'm willing to
risk that it rings a second or two later or earlier than expected.
(If the alarm is set to go off at a specific time, the duration might
be longer than expected.  If the alarm is set for a specific number of
seconds, then it might go off at an earlier time than expected.)
As long as the specification is clear, I think that is OK.
-- 
	--Per Bothner
per at bothner.com   http://per.bothner.com/