delving into different calendars. advice?

gregorian, hebrew, ecclesiatic, etc

[httpwebwitch]

I'm getting into a situation where I need to do date calculations in various non-secular calendars.

For instance, my PHP application needs to calculate an integer, which expresses "how many days until Purim".

or it may do calculations with a date object, which defines "when is the next date of Easter".

I have a feeling these lunar-based calendars and moveable feasts are going to be a bigger challenge than I'm prepared for.

Any advice before I get started?

[RonPK]

[php.net...] may be of use. PHP even turns out have a function called easter_date([year]). Christian Easter, probably; which offcourse differs from Orthodox and Jewish Easter :)

[httpwebwitch]

I think the simplest option will be to get dates for the next 30 years and keep them in a table. I'm not trying to calculate Easter in the year 1200 BCE, I just need to know when it'll fall next year, then the year after that, etc.

[g1smd]

"The Calendar FAQ" is probably the most comprehensive document on the subject. Google it.