FUNCTION findCommonDir RETURNS CHAR(
   i_cdirs        AS CHAR,
   i_cseparator   AS CHAR
):

   DEF VAR idir      AS INT.
   DEF VAR idepth    AS INT.
   DEF VAR cdir      AS CHAR EXTENT.
   DEF VAR lsame     AS LOGICAL INITIAL TRUE.
   DEF VAR cresult   AS CHAR.

   EXTENT( cdir ) = NUM-ENTRIES( i_cdirs, '~n' ).

   DO idir = 1 TO NUM-ENTRIES( i_cdirs, '~n' ):
      cdir[ idir ] = ENTRY( idir, i_cdirs, '~n' ).
   END.

   DO idepth = 2 TO NUM-ENTRIES( cdir [ 1 ], i_cseparator ) WHILE lsame:
      DO idir = 1 TO EXTENT( cdir ) - 1 WHILE lsame:
         lsame =  (
                     ENTRY( idepth, cdir [ idir ], i_cseparator ) =
                     ENTRY( idepth, cdir [ idir + 1 ], i_cseparator )
                  ).
      END.
      IF lsame THEN
         cresult = cresult + i_cseparator + ENTRY( idepth, cdir [ 1 ], i_cseparator ).
   END.

   RETURN cresult.

END FUNCTION.