case SUB:
expressions[index] = mode == INTEGER ? new SubInteger(exp,
expressions[index + 1]) : new SubDouble(exp, expressions[index + 1]);
break;
case GT:
expressions[index] = new GTCheck(exp, expressions[index + 1]);
break;
case LT:
expressions[index] = new LTCheck(exp, expressions[index + 1]);
break;
case EQ: