Done ISO 8601 date vars and functions

[K_Meinhard]

Hi Rex,

I'd still like to see fulkl support for ISO 8601 date formats in TCC.

Especially the should be intvars

_ISODOWI Numeric day of the week (Mon = 1, etc.)
_ISORDATE Current ISO 8601 ordinal date (yyyy-ddd)
_ISOWDATE Current ISO 8601 week date (yyyy-Www-d)
_ISOWEEK Week of the year pursuant to ISO 8601
_ISOWYEAR Current ISO 8601 week date year

besides the existing _ISODATE

@AGEDATE
@DATECONV
@MAKEAGE
@MAKEDATE

should support the additional switches

5 - ISO 8601 international format (yyyy-Www-d) week date
6 - ISO 8601 international format (yyyy-ddd) ordinal date

and there should be the additional variable functions

@ISODOWI[date] Numeric day of the week (Mon = 1, etc.)
@ISOWEEK[date] Week of the year pursuant to ISO 8601

I think it is essential that TCC supports international time and date
standards. Since all these intvars and var functions are implemented in
4DOS and the code is available, it should be easy and would maintain
compatibility.

* Klaus Meinhard *
4DOS Info - Info for DOS
www.4dos.info