PHP defines the first week of the year as either starting with the years first sunday or first monday (strftimes %U and %W switches). This doesn't honour e.g. the danish standards.

According to danish standards, and several other european countries i would guess, the first week of the year is defined as:

The first Thursday of any given year will always be in the first week of that year.

Thus week 1 of the year of 1998 was defined as 29/12-1997 to 4/1-1998.

The math behind this algorithm is pretty simple, so i hope it can be implemented as part of php 4.

If you will point me to where the code is in the sourcetree that handles these calculations, i will be happy to implement it (though i am not very strong in c, but i guess you can always clean it for memoryleaks and such when i deliver the raw algortithms)

/Martin Jespersen