/* $DOC$
   $NAME$
      ft_AcctWeek()
   $CATEGORY$
      Date/Time
   $ONELINER$
      Return accounting week data
   $SYNTAX$
      ft_AcctWeek( [ <dGivenDate> ], [ <nWeekNum> ] ) -> aDateInfo
   $ARGUMENTS$
      <dGivenDate> is any valid date in any date format.  Defaults
      to current system date if not supplied.

      <nWeekNum> is a number from 1 to 52 signifying a week.
      Defaults to current week if not supplied.
   $RETURNS$
      A three element array containing the following data:

         aDateInfo[ 1 ] - The year and week as a character string "YYYYWW"
         aDateInfo[ 2 ] - The beginning date of the accounting week
         aDateInfo[ 3 ] - The ending date of the accounting week
   $DESCRIPTION$
      ft_AcctWeek() returns an array containing data about the
      accounting week containing the given date.

      An accounting period has the following characteristics:

      If the first week of the period contains 4 or more 'work'
      days, it is included in the period; otherwise, the first
      week was included in the prior period.

      If the last week of the period contains 4 or more 'work'
      days it is included in the period; otherwise, the last week
      is included in the next period.  This results in 13 week
      'quarters' and 4 or 5 week 'months'.  Every 5 or 6 years, a
      'quarter' will contain 14 weeks and the year will contain 53
      weeks.
   $EXAMPLES$
      // get info about accounting week containing 1990-09-15
      aDateInfo := ft_AcctWeek( hb_SToD( "19900915" ) )
      ? aDateInfo[ 1 ]   //  199037       (37th week)
      ? aDateInfo[ 2 ]   //  1990-09-09   beginning of week 37
      ? aDateInfo[ 3 ]   //  1990-09-15   end of week 37

      // get info about accounting week 25 in year containing 1990-09-15
      aDateInfo := ft_AcctWeek( hb_SToD( "19900915" ), 25 )
      ? aDateInfo[ 1 ]   //  199025
      ? aDateInfo[ 2 ]   //  1989-06-17   beginning of week 25
      ? aDateInfo[ 3 ]   //  1990-06-23   end of week 25
   $SEEALSO$
      ft_DateCnfg(), ft_AcctMonth(), ft_AcctQtr(), ft_AcctYear()
   $END$
 */