public static Operator getBuiltinOperator(final char symbol, final int numArguments) {
        switch(symbol) {
            case '+':
                if (numArguments != 1) {
                    return builtinOperators[INDEX_ADDITION];
                }else{
                    return builtinOperators[INDEX_UNARYPLUS];
                }
            case '-':
                if (numArguments != 1) {
                    return builtinOperators[INDEX_SUBTRACTION];
                }else{
                    return builtinOperators[INDEX_UNARYMINUS];
                }
            case '*':
                return builtinOperators[INDEX_MUTLIPLICATION];
            case '/':
                return builtinOperators[INDEX_DIVISION];
            case '^':
                return builtinOperators[INDEX_POWER];
            case '%':
                return builtinOperators[INDEX_MODULO];
            default:
                return null;
        }
    }