Udf4ORA version 0.5.0 has just been released
http://perso.orange.fr/Udf4ORA/

That UDF library based on rFunc library,
contains today 33 Oracle like build-in functions (for Windows):
- SYSDATE()
- TO_CHAR(num)
- TO_CHARD(ts,fmt) fmt: DDD,DD,D,DAY,IW,MM,MON,YYYY,YY,HH24,MI,SS
- TO_DATE(ts,fmt) fmt: DDD,DD,D,IW,MM,MON,YYYY,YY,HH24,MI,SS
- TO_NUMBER(str)
- TRUNCD(ts,fmt) fmt: YY,MM,IW,DD,HH,MI,SS
- ...

Main changes since initial version are about dates conversions:

- support for ISO weeks added
(day numbering according to FRENCH territory)
to_date('2004-53','YYYY-IW') --> 2004.12.27 00:00:00
to_date('2005-52-7','YYYY-IW-D') --> 2006.01.01 00:00:00
to_chard(date'2005-01-04','YYYY IW D') --> '2005 01 2'
truncd(sysdate(),'IW') --> 2006.12.18 00:00:00

- default dates added
to_date('344','DDD') --> 2006.12.10 00:00:00
to_date('50','IW') --> 2006.12.11 00:00:00

Regards
PAscal

Nb: help for Linux port would be appreciated