$CPU 8086          ' make compatible with XT systems
$LIB ALL OFF       ' turn off all PowerBASIC libraries
$ERROR ALL OFF     ' turn off all PowerBASIC error checking
$OPTIMIZE SIZE     ' optimize for smaller code
'$COMPILE EXE       ' compile to a UNIT (.PBU)
$COMPILE UNIT      ' compile to a UNIT (.PBU)

DEFINT A-Z         ' Required for all numeric functions, forces PB to not
                   ' include floating point in UNIT (makes it smaller)
'/*------------------------------------------------------------------*/
$CODE SEG "MLIB4"
'/*------------------------------------------------------------------*/
' DELSTR(STRING,START,LENGTH)
'     Delete subString.
'     Deletes the sub-string of STRING that begins at start
'     character and is of LENGTH.  If LENGTH is 0 then the rest of
'     the string is deleted (including the character at start).  If
'     START is greater than the length of STRING then the string is
'     returned unchanged.
'     EXAMPLE:  DELSTR('abcd',3)        = 'ab'
'               DELSTR('abcde',3,2)     = 'abe'
'               DELSTR('abcde',6)       = 'abcde'
'/*------------------------------------------------------------------*/
    FUNCTION DELSTR(BYVAL X AS STRING, BYVAL S AS INTEGER, BYVAL L AS INTEGER) PUBLIC AS STRING
      TL = LEN(X)
      IF S > TL THEN
        XRET$ = X
      ELSE
        IF L = 0 THEN
          XRET$ = LEFT$(X,S-1)
        ELSE
          TL$ = LEFT$(X,S-1)
          IF (S+L) > TL THEN
            TR$ = ""
          ELSE
            TR$ = RIGHT$(X,TL-S-L+1)
          END IF
          XRET$ = TL$ + TR$
        END IF
      END IF
      DELSTR = XRET$
    END FUNCTION
'/*------------------------------------------------------------------*/
'  CLS
'  A$ = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
'  PRINT "1234567890123456789012345678901234567890"
'  PRINT A$
'  PRINT DELSTR(A$,3,0)
'  PRINT DELSTR(A$,3,2)
'  PRINT DELSTR(A$,20,30)
'  INPUT Z