RFC: Time Library 0.3
ashley at semantic.org
Mon Feb 6 03:00:44 EST 2006
Please take a look at my third draft of a replacement for the standard
Take a look at the Haddock documentation:
Download the source:
Or keep up-to-date:
darcs get http://semantic.org/TimeLib/TimeLib/
It needs GHC 6.4.1. (I haven't tested with 6.4 or other compilers.) It
consists of two separate Cabal packages, "fixed" and "time", which can
be installed in the usual way. See the README file.
This release should be close to being ready to become part of the
libraries distributed with some future version of GHC. I'm interested in
any remaining issues.
Major changes since 0.2:
* The code has been reorganised into two separate packages, "fixed",
containing only Data.Fixed for fixed-point arithmetic, and "time",
containing everything else.
* The modules in "time" have been reorganised. The three "first level"
modules, Data.Time.*, contain functionality that most ordinary users
want. The "root" module, Data.Time simply re-exports these three. The
"second level" modules, Data.Time.*.*, contain more specialised
Some points (largely repeated from the 0.2 RFC):
1. There is no leap second table provided, though there is a type
(LeapSecondTable) for such things. Any software compiled with a fixed
table would soon become out of date.
2. There is no table of time-zones provided, since these also change.
However, if there's a good way of getting this from the TZ database on
the machine, I'll add that.
It is actually possible to get the local time-zone for any given time,
indeed one of the test programs finds your local summertime transitions.
The Timezone type includes name, minutes of offset, and a "summertime"
3. The TimeLocale type comes from the already existing System.Locale.
4. The "fixed" package includes Data.Fixed which provides a fixed-point
arithmetic type (wrapper around Integer). It allows dealing with seconds
as a single thing, rather than as an integer/picoseconds pair. It should
probably be merged into base.
5. I don't have any text-parsing functionality for times. This is a fair
amount of work, so it would be good to know sensible requirements.
6. Time as measured by the CPU since system startup remains in
System.CPUTime, which TimeLib does not intend to replace.
Ashley Yakeley, Seattle WA
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