PACKET isub replace DEFINES ISUB, replace : 
 
INT OP ISUB (TEXT CONST t, INT CONST i) : 
 
  INT CONST ii := i + i; 
  code (t SUB ii - 1) + 256 * code (t SUB ii) 
 
END OP ISUB; 
 
PROC replace (TEXT VAR t, INT CONST i, wert) : 
 
  INT CONST ii := i + i; 
  replace (t, ii - 1, code (wert MOD 256)); 
  replace (t, ii,  code (wert DIV 256 MOD 256)) 
 
END PROC replace 
 
END PACKET isub replace;