ISO year week day to date

Trying to get date out of three of numbers. Three numbers are ISO standard year, ISO standard week and number of a day in a week. The first day of a week is Monday.

select to_date ('2010 40 4','iyyy iw d') from dual;

ORA-01820: format code cannot appear in date input format
01820. 00000 -  "format code cannot appear in date input format"

A date specification contained an invalid format code. Only the following
may be specified when entering a date: year, month, day, hours, minutes,
seconds, Julian day, A.M./P.M. and B.C./A.D.

select to_timestamp ('2010 40 4','iyyy iw d') from dual;

Surprise, no luck, the same error.

From Oracle support formely known as metalink can be found a statement that the feature has not been in such priority to be implemented. Build your own function. I am too lazy to do that. And as I know the timerange I am interested in I use brute force. Use data. We are in a database. It is built to store data. I will use that ability.

create table isoyearweekday_to_date(
isoyearweekday number(7) constraint isoyearweekday_to_date_pk primary key
, dat date not null) 
organization index;

insert into isoyearweekday_to_date 
select to_char(d,'iyyyiwd')
     , d 
  from (
   select to_date('17991231','yyyymmdd')+level d
     from dual 
   connect by level <= to_date('22000101','yyyymmdd')-to_date('18000101','yyyymmdd')+1
  )
;

select * from isoyearweekday_to_date where isoyearweekday = 2010404
;

2010404 07.10.2010