Mini Calculator

calc.cs

namespace Calculator
{
    using static System.Console;
    using Sprache;
    using System.Linq;
    
    internal class Program
    {
        public static void Main(string[] args)
        {
            IOperation<int> Build() 
                => Operation.token.Token().Parse(args.First());
            WriteLine($"Result: {Build().Calc()}");
        }
    }
    public enum OperationType : ushort
    {
        Mul = 42, Div = 47,
        Sum = 43, Sub = 45
    }
    public struct Operation : IOperation<int>
    {
        public int Value1, Value2;
        public OperationType Type { get; set; }
        public int Calc()
        {
            switch (Type)
            {
                case OperationType.Div: return Value1 / Value2;
                case OperationType.Mul: return Value1 * Value2;
                case OperationType.Sum: return Value1 + Value2;
                case OperationType.Sub: return Value1 - Value2;
                default: return default;
            }
        }

        public static unsafe implicit operator Operation((int n1, int n2, ushort op) raw) => *(Operation*)&raw.n1;

        public static Parser<Operation> token =
            from num1 in Parse.Number
            from op in Parse.Chars('+', '-', '/', '*')
            from num2 in Parse.Number
            select (Operation)(int.Parse(num1), int.Parse(num1), op);
    }
    public interface IOperation<out T>
    {
        OperationType Type { get; set; }
        T Calc();
    }
}