Manipulating Old Dates

[Ray G. Miller]

Ken Norris asked:

>> Rob,
>> 
>> In the product I'm working on with a client right now, we keep track of
>> birthdates. And the way we manage it is by setting the centuryCutoff to
>> one less than the current year (so right now it's "03"). This means that
>> as long as someone is 99 years old or less, we're OK. It's not a perfect
>> solution, but it's working so far.
>  
>


 > What do we do with _really_ old dates, like weather logs from 
California missions 300 years ago? Ideas? Ken N.

The centuryCutoff is a real bad idea. HyperCard had it almost correct: "true date" up to +/- AD 32000...

About a thousand cycles ago on the MetaCard list, this basic flaw in the engine was hammered around for a month or more, I believe Rob Cozen was one of the contributors. Someone came up with a Julian/Gregorian convertor: worked up to (down to?) Jan 1, 1801.

I battled with it for another month or so, but it's pretty much a kudge: lookup tables for really olden times. 

This is not merely quirky, it's needed in lots of APPs. I have three projects going which require time spans greater than 100 years. If the filks at Apple had this solved, surely the RevTeam can do it... or this group.

Let's see, there's 365.24+... days in a year ;-)


Ray

Ray G. Miller
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