// String.charAt(int)
} else if (methodName.equals("charAt") && numArgs == 1) {
UnaryOperation op;
Integer arg = trackInteger(expr.getArg(0));
if (arg != null) {
op = new CharAt1(arg);
} else {
op = new CharAt2();
}
Variable result = factory.createVariable(VariableType.PRIMITIVE);
factory.addStatement(new BasicUnaryOp(result, callee, op));