Re: Time library design proposal

2 Feb 2005

      Bayley, Alistair wrote:
...
...
From: Keean Schupke [mailto:k.schupke@imperial.ac.uk]
data Gregorian = Gregorian {
   second :: Int,
   minute :: Int,
   hour :: Int,
   dayOfMonth :: Int,
   dayOfWeek :: Int,
   weekOfYear :: Int,
   monthOfYear :: Int,
   Year :: Int } -- enumerations may make more sense for 
dayOfWeek/monthOfYear
I don't like the redundancy here. dayOfWeek and weekOfYear can (and should)
be derived from the dayOfMonth+monthOfYear+year. Having to specify them in
addition to the other fields is a major PITA, and one of the reasons the
current CalendarTime library is so unsavoury (why do I need to say what day
of the week it is? pah).
Alistair.
For some functions it makes sense, for reverse calculations (Calendar -> 
TAI) it can save
a lot of time to just fill out some fields... I was thinking of cron 
like functionality where you want
to represent a repeat time (like every monday at 8pm)... But this would 
require each field to
have a type like:

data Gregorian = Gregorian {
    second :: [Int],
    minute :: [Int],
    hour :: [Int],
    dayOfMonth :: [Int],
    dayOfWeek :: [Int],
    weekOfYear :: [Int],
    monthOfYear :: [Int],
    year :: [Int] }

anytime = {
    second = [],
    minute = [],
    hour = [],
    dayOfMonth = [],
    dayOfWeek = [],
    weekOfYear = [],
    monthOfYear = [],
    year = [] }

recordMyProgram = anytime { dayOfWeek = [1,3], hour = [21] }

So my program gets recorded every monday and wednesday at 9pm.

	Keean.