!+
!					Tools Group
!					Space Telescope Science Institute
!					3700 San Martin Drive
!					Baltimore, MD 21218
!
!  NAME
!	SCAN_STRING_UTILS
!
!  DESCRIPTION
!	File contains a set of SCAN string utilities that can
!	make life easy ...
!
!  RETURN VALUE
!
!  HISTORY
!	11/88		Bauer		Created for use in MMSGEN
!-

MODULE SCAN_STRING_UTILS;

    !
    !	Substitutes a string for another
    !
    PROCEDURE substitute_string ( change_this : STRING,
				  to_that     : STRING,
				  in_this_string : STRING );


	DECLARE temp   : STRING;
	DECLARE s1, len1, len2 : INTEGER;


	s1 = INDEX (in_this_string, change_this);

	IF s1 = 0
	THEN
	    RETURN;
	END IF;

	len1 = LENGTH(in_this_string);
	len2 = LENGTH(change_this);

	temp = in_this_string[1..s1-1];
	IF len1-len2+1 = s1
	THEN
		temp = temp & to_that;
	ELSE
		temp = temp & to_that & in_this_string[(s1+len2)..];
	END IF;

	in_this_string = temp;

    END PROCEDURE;

    !
    !	Substitutes all occurrences of a string for another
    !
    PROCEDURE substitute_all_strings ( change_this : STRING,
				       to_that     : STRING,
				       in_this_string : STRING );


	DECLARE temp1, temp2   : STRING;
	DECLARE s1, len1, len2 : INTEGER;

	temp1 = in_this_string;
	temp2 = in_this_string;

	CALL substitute_string (change_this, to_that, temp1);
	
	WHILE (temp1 <> temp2);
			
	    temp2 = temp1;
	    CALL substitute_string (change_this, to_that, temp1);

	END WHILE;
 
	in_this_string = temp1;
	
    END PROCEDURE;

END MODULE;