PROCEDURE fred$extract(delimiter,reference_string,context)
   LOCAL len,		! Length of reference string
       	temp,		! Work area for reference string
	temp1,		! Location of delimiter
	start,          ! Start of substring
	end,            ! End of substring
	sub_length,     ! Length of substring
 	sub_string;	! Element of reference string to return

   temp := reference_string;
   len := LENGTH (temp);
   if context = 0 then
      temp1 := INDEX (SUBSTR (temp,1,len),delimiter);
      if temp1 = 0 then
	 end := len;
      else
	 end := temp1 - 1;
      endif;
      sub_length := end;
      start := 1;
   else               
      end := fred$x_extract_end;
      if end = len then
	 RETURN (0);
      endif;
      start := end + 2;
      temp1 := INDEX (SUBSTR (temp,start,len),delimiter);
      if temp1 = 0 then
         end := len;
         sub_length := end;
      else
	 end := end + temp1;
	 sub_length := temp1 - 1;
      endif;
   endif;                                          

   sub_string := SUBSTR (temp,start,sub_length);
   fred$x_extract_start := start;
   fred$x_extract_end := end;

   RETURN (sub_string);
ENDPROCEDURE;