[Fwd: Re: [fpc-devel] Magic numbers used in TryEncodeDate]

[Marco van de Voort]

> But I recommend looking these things up somewhere before writing it down
> in the docs. (i.e. about the precise meaning of the Gregorian vs. the
> Julian calendar) This is just my IIRC :)

There is a very exhaustive calendar faq on the internet. And if you read it,
then you will understand that implementing full calendar support will result
in an immensely overweight system that is not used 99% of the time.

So the "historic" datetime routines and the normal, 1950+ routines
should be kept separate.

This is also because the conversion to the Gregorian calendar is dependant
on where you live. Some Orthodox countries only converted in the 20th
century.

Most calendar systems only implement a simplified model of the date system
(e.g. what can be easily caught with a few equations), and don't tackle the
place-specific issues, and the myriads of exceptions. However for real
historic date use, you'll need that.