C#•11mo ago

better way to do this?

19 Replies

Thinker•11mo ago

Just this constructor? In C# 12 you can do

public class BoxCollider2D(Vector2 size)
{
    private Vector2 size = size;
}

public class BoxCollider2D(Vector2 size)
{
    private Vector2 size = size;
}

Otherwise, there's not really any better way to write such a small constructor

mtreit•11mo ago

Shouldn't that just be:

public class BoxCollider2D(Vector2 size)
{
}

public class BoxCollider2D(Vector2 size)
{
}

Thinker•11mo ago

Yeah it could

jcotton42•11mo ago

there's a slight difference, yours doesn't necessarily create a field but for most cases they're interchangeable

mtreit•11mo ago

It's unclear from the OP what this.size is intended to be...with the way people case things around here it could be a property 😄

nohopestage•11mo ago

I like how in Kotlin you can do this:

class BoxCollider2D(private val size: Vector2) { }

class BoxCollider2D(private val size: Vector2) { }

Wish C# had that feature So size would be a private field?

Angius•11mo ago

No modifiers, alas, but that's what primary ctors are

class BoxCollider2D(Vector2 size) {}

class BoxCollider2D(Vector2 size) {}

nohopestage•11mo ago

Yeah, still pretty nice So they're not object members

MODiX•11mo ago

Angius

sharplab.io (click here)

public class Foo(int bar) {
    public void Write() => Console.Write(bar);
};

public class Foo(int bar) {
    public void Write() => Console.Write(bar);
};

Try the /sharplab command! | React with ❌ to remove this embed.

Angius•11mo ago

The compiler will generate

public class Foo
{
    private int <bar>P;

    public Foo(int bar)
    {
        <bar>P = bar;
        base..ctor();
    }

    public void Write()
    {
        Console.Write(<bar>P);
    }
}

public class Foo
{
    private int <bar>P;

    public Foo(int bar)
    {
        <bar>P = bar;
        base..ctor();
    }

    public void Write()
    {
        Console.Write(<bar>P);
    }
}

nohopestage•11mo ago

Oh, I see

The compiler creates storage for any primary constructors only when that parameter is accessed in the body of a member of your type. Otherwise, the primary constructor parameters aren't stored in the object. Primary constructor parameters aren't members of the class. For example, a primary constructor parameter named param can't be accessed as this.param. Weird So they're not, but they also are Or the other way around

Angius•11mo ago

Yeah, if you just do

public class Foo(int bar);

public class Foo(int bar);

the compiler will generate

public class Foo
{
    public Foo(int bar)
    {
    }
}

public class Foo
{
    public Foo(int bar)
    {
    }
}

It's not like records, those actually generate properties and a bunch more code

nohopestage•11mo ago

But here in the method the parameter can't be used as this.bar, right?

Angius•11mo ago

Let's see

MODiX•11mo ago

Angius

REPL Result: Failure

public class Foo(int bar) {
    public void Write() => Console.Write(this.bar);
};
new Foo(69).Write();

public class Foo(int bar) {
    public void Write() => Console.Write(this.bar);
};
new Foo(69).Write();

Exception: CompilationErrorException

- 'Foo' does not contain a definition for 'bar' and no accessible extension method 'bar' accepting a first argument of type 'Foo' could be found (are you missing a using directive or an assembly reference?)

- 'Foo' does not contain a definition for 'bar' and no accessible extension method 'bar' accepting a first argument of type 'Foo' could be found (are you missing a using directive or an assembly reference?)

Compile: 453.784ms | Execution: 0.000ms | React with ❌ to remove this embed.

Angius•11mo ago

It seems no, it cannot

MODiX•11mo ago

Angius

REPL Result: Success

public class Foo(int bar) {
    public void Write() => Console.Write(bar);
};
new Foo(69).Write();

public class Foo(int bar) {
    public void Write() => Console.Write(bar);
};
new Foo(69).Write();

Console Output

Compile: 413.586ms | Execution: 25.561ms | React with ❌ to remove this embed.

Angius•11mo ago

It's fine without this, though Which, let's be honest, who ever uses this. explicitly

nohopestage•11mo ago

Some people do, but I'm not one of them

Gaming

Programming

better way to do this?