C REDO COMMAND PROGRAM
C MICHAEL A. SAVERINO 10/13/82
C-----------------------------------------------------------------------------
C THIS PROGRAM READS IN A LOCAL SYMBOL FROM THE REDO COMMAND LINE 
C INTERPRETER, ENABLES THE USER TO EDIT THE CHARACTER STRING ASSOCIATED
C WITH THE SYMBOL, AND RETURNS THE SYMBOL TO THE REDO COMMAND LINE INTERPRETER.
C IF THE USER WISHES NOT TO EDIT THE STRING, JUST HIT <ret> IN RESPONSE TO
C THE Edit? PROMPT.  IF THE USER WISHES TO EDIT THE STRING, TYPE THE OLD
C STRING AND THE NEW STRING SEPERATED BY A "|". (i.e. IF THE COMMAND
C SHOW USERS NEEDS TO BE CHANGED TO SHOW SYSTEM, THEN THE USER MUST TYPE
C USERS|SYSTEM IN RESPONSE TO THE Edit? PROMPT). THE NEW COMMAND WILL BE
C DISPLAYED AND YOU WILL BE PROMPTED FOR FURHTER CHANGES BEFORE EXECUTION.
C HIT RETURN IN RESPONSE TO THE Edit? PROMPT IF NO FURHTER CHANGES ARE REQUIRED
C-----------------------------------------------------------------------------
	CHARACTER*255 IN_LINE,OUT_LINE,CHG_BUF
	INTEGER BUF,STR$TRIM,LEN,LENCHG,STR$POSITION,DIV,CHK_OLD_STR
     *  ,STR$REPLACE
	CALL LIB$GET_SYMBOL('PREVIOUS_LINE',IN_LINE,BUF)! READ IN PREVIOUS SYM.
999	TYPE*,'Command: '//IN_LINE(1:BUF)               
99	CALL LIB$GET_FOREIGN(CHG_BUF,'Edit? ',LENCHG)   !PROMPT FOR EDIT STRING
	IF (LENCHG.EQ.0)THEN				!EXIT OF NO CHANGES
		OUT_LINE=IN_LINE
	ELSE
		DIV=STR$POSITION(CHG_BUF,'|')		!PARSE CHANGE STRING
		IF (DIV.EQ.0)THEN
			PRINT*,'Change command syntax error!!!'
			GOTO 99
		ENDIF					
		CHK_OLD_STR=STR$POSITION(IN_LINE(1:BUF),CHG_BUF(1:DIV-1))
			IF(CHK_OLD_STR.EQ.0)THEN
			PRINT*,'Change string not found!!!'
			GOTO 99				!ERROR IF NO MATCH
		ENDIF
		CALL STR$REPLACE(IN_LINE,IN_LINE,CHK_OLD_STR,
     *          CHK_OLD_STR+DIV-2,CHG_BUF(DIV+1:LENCHG))!SUBSTITUTE STRINGS
		CALL STR$TRIM(IN_LINE,IN_LINE,BUF)
		GOTO 999
	ENDIF
	CALL STR$TRIM(OUT_LINE,OUT_LINE,LEN)
	CALL LIB$SET_SYMBOL('CURRENT_LINE',OUT_LINE(1:LEN))
	CALL EXIT					!SET NEW STRING TO
	END						!CURRENT SYMBOL