Re: [Scheme-reports] [scheme-reports-wg2] Date and time arithmetic library proposal for R7RS large Scheme
John Cowan 22 Nov 2010 17:02 UTC
Neil Van Dyke scripsit:
> There are also important decisions to make, like the semantics of
> mixed-precision arithmetic on, say, time points.
Can you clarify this?
> A few years ago, I spent person-weeks implementing most of ISO 8601, and
> the API that I arrived at was necessarily (I felt) not nearly as neat
> and tidy as TimeAdvancedCowan.
I have another proposal in the works for periods, intervals, and recurring
intervals, but I consider them less complicated. Note also that date
objects are broader than ISO 8601: they can contain values that don't
constitute time points, such as '((month . 4) (day-of-month . 2)).
XML Schema notates this as "--4-2", but I don't know why.
Can we have a pointer to docs for your implementation? In standards work,
API buccaneering is a good thing.
Note: I have just added date->alist to get the fields out of a date
object in bulk.
> However, the experience has led me to believe that RnRS should make
> a conscious, informed decision of how much of ISO 8601 to support,
> even though the answer might be "only what Java does".
I looked at the official Java support, and it was a horrible mess, so I
worked from Joda Time instead. It's overly complicated and Javaesque,
so I tried to boil it down as much as seemed feasible.
--
Kill Gorgun! Kill orc-folk! John Cowan
No other words please Wild Men. cowan@ccil.org
Drive away bad air and darkness http://www.ccil.org/~cowan
with bright iron! --Ghan-buri-Ghan http://www.ccil.org/~cowan
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