public function getSymbols()
    {
        $symbols = [
            Number::class,

            Separator::class,

            ClosingBracket::class,
            OpeningBracket::class,

            PiConstant::class,
            EConstant::class,
            LogTwoEConstant::class,
            LogTenEConstant::class,
            LnTwoConstant::class,
            LnTenConstant::class,
            PiTwoConstant::class,
            PiFourConstant::class,
            OnePiConstant::class,
            TwoPiConstant::class,
            SqrtPiConstant::class,
            TwoSqrtPiConstant::class,
            SqrtTwoConstant::class,
            SqrtThreeConstant::class,
            SqrtOneTwoConstant::class,
            LnPiConstant::class,
            EulerConstant::class,

            AdditionOperator::class,
            DivisionOperator::class,
            ExponentiationOperator::class,
            ModuloOperator::class,
            MultiplicationOperator::class,
            SubtractionOperator::class,

            AbsFunction::class,
            ACosFunction::class,
            ACosHFunction::class,
            ASinFunction::class,
            ASinHFunction::class,
            ATanFunction::class,
            ATanHFunction::class,
            ATanTwoFunction::class,
            CeilFunction::class,
            CosFunction::class,
            CosHFunction::class,
            DegToRadFunction::class,
            EnFunction::class,
            ExpFunction::class,
            ExpMOneFunction::class,
            FloorFunction::class,
            FModFunction::class,
            GetRandMaxFunction::class,
            HypotFunction::class,
            LogFunction::class,
            LogOnePFunction::class,
            LogTenFunction::class,
            MaxFunction::class,
            MinFunction::class,
            MTGetRandMaxFunction::class,
            MTRandFunction::class,
            PowFunction::class,
            RadToDegFunction::class,
            RandFunction::class,
            RoundFunction::class,
            SinFunction::class,
            SinHFunction::class,
            SqrtFunction::class,
            TanFunction::class,
            TanHFunction::class,
        ];

        return $symbols;
    }