C#•3mo ago

✅ how do i override built-in methods?

i come from python where you can override methods in a class to work a certain way. for example, for use in the == operator, you can override a class to modify the behaviour of the __eq__ method which checks if two objects are equal. if i wanted to do an XOR on a class that holds an internal value, how can i override it so it works on the internal value instead of the class itself?

12 Replies

it’s raining outsideOP•3mo ago

i want to make a superset of a ulong by adding extra methods, but i dont know if you can subclass that or not and how it would affect behaviour in code no you cannot in python you can subclass datatypes which i find pretty handy

Angius•3mo ago

Operator overloading is a thing in C#, yes Far as subclassing an ulong goes... I don't think that's possible You would have to use composition over inheritance here Or make use of extension methods

shadi•3mo ago

i think this would work on my phone so can't test public static MyClass operator ^ (MyClass a, MyClass b) { return new MyClass( a.Value ^ b.Value); }

Angius•3mo ago

Yep

MODiX•3mo ago

Angius

REPL Result: Success

public record struct MyUlong(ulong Value)
{
    public static MyUlong operator ^(MyUlong a, MyUlong b)
        => new(a.Value ^ b.Value);
}

var x = new MyUlong(718);
var y = new MyUlong(421);

x^y

public record struct MyUlong(ulong Value)
{
    public static MyUlong operator ^(MyUlong a, MyUlong b)
        => new(a.Value ^ b.Value);
}

var x = new MyUlong(718);
var y = new MyUlong(421);

x^y

Result: MyUlong

{
  "value": 875
}

{
  "value": 875
}

Compile: 389.060ms | Execution: 104.519ms | React with ❌ to remove this embed.

jcotton42•3mo ago

Yeah you can’t, value types are sealed.

Anton•3mo ago

python doesn't have value types though

jcotton42•3mo ago

@it’s raining outside for extra methods on ulong, look into extension methods.

public static class MyExtensions
{
  public ulong Triple(this ulong u) => u * 3;
}

ulong ul = 2;
ul.Triple();

public static class MyExtensions
{
  public ulong Triple(this ulong u) => u * 3;
}

ulong ul = 2;
ul.Triple();

it’s raining outsideOP•3mo ago

this works? how?

canton7•3mo ago

https://learn.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/extension-methods

Extension Methods - C#

Extension methods in C# enable you to add methods to existing types without creating a new derived type, recompiling, or otherwise modifying the original type.

Angius•3mo ago

https://tenor.com/view/magic-gif-23835991

Tenor

Angius•3mo ago

It's basically syntactic sugar over just calling it as a regular static method 79.Stuff() instead of Extensions.Stuff(79)

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✅ how do i override built-in methods?