On Tue, Jan 03, 2012 at 01:04:20PM -0200, Thiago Negri wrote:

Hi,

How does Haskell handle TimeZone? Do I need to use Oslon to have a historical database of TimeZones in Haskell?

I tried reading the package description and everything, but it seems complicated. Is there any easy to follow tutorial available?

For example, here in Brazil the daylight savings rules change every year. How do I update the Haskell Data.Time.* packages to know of the new rules? Or does it uses the TimeZone database from O.S.?

I'm looking for a solution that works in any platform (mac, linux, windows).

Hi Thiago, The time package by itself does not know about changing time zone rules. However, the timezone-series package (http://hackage.haskell.org/package/timezone-series) claims to extend Data.Time with exactly that capability. You can use it in conjunction with the timezon-olson package (http://hackage.haskell.org/package/timezone-olson) for reading Olson timezone databases. (Disclaimer: I have never used these packages myself.) It would be really great if someone wrote an easy to follow tutorial for dealing with time in Haskell, but as far as I know no one has yet done so. The time package is indeed complicated, but unfortunately that's because representing time is a complicated subject. Any simpler and it would be wrong. -Brent