RE: [Haskell-cafe] Re: Can't do basic time operations with System.Time

On 21 January 2005 21:50, John Goerzen wrote:

On 2005-01-21, Peter Simons wrote:

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24 * ((fromIntegral $ tdDay td) + 30 * ((fromIntegral $ tdMonth td) + 365 * (fromIntegral $ tdYear td)))))

I was wondering: Does this calculation account for leap years? Does it have to?

I also wondered about all months being 30 days. But this exact algorithm is used in fptools' normalizeTimeDiff, and it seems to work out correctly, so I guess the timeDiff functions assume that every month has 30 days and every year has 365.

normalizeTimeDiff (and TimeDiff in general) is wrong. I wouldn't recommend using it. There's the TimeExts library in the lang package, which might be useful to you. Cheers, Simon