Uninomicon

You've loaded an old revision of the document! If you save it, you will create a new version with this data.

====== IEnumerator ======

Notes on the underlying implementation of C# generators (which are used in Unity for coroutines).

===== Lambda function DisplayClass classes are initialized at the start of the function =====
The following code, in SharpLab decompiles it as:
<code c#>
using System;
using System.Collections;
public class C {
    public IEnumerator M() {
        int x = 5;
        yield return Test(() => x > 5);
        yield return 5;
        yield return 5;
        yield return 5;
    }
    
    public IEnumerator Test(Func<bool> func) {
        yield return func();
    }
}
</code>
<code>
.. snipped
private bool MoveNext()
        {
            switch (<>1__state)
            {
                default:
                    return false;
                case 0:
                    <>1__state = -1;
                    <>8__1 = new <>c__DisplayClass0_0();
                    <>8__1.x = 5;
                    <>2__current = 5;
                    <>1__state = 1;
                    return true;
                case 1:
                    <>1__state = -1;
                    <>2__current = 5;
                    <>1__state = 2;
                    return true;
                case 2:
                    <>1__state = -1;
                    <>2__current = <>4__this.Test(new Func<bool>(<>8__1.<M>b__0));
                    <>1__state = 3;
                    return true;
                case 3:
                    <>1__state = -1;
                    <>2__current = 5;
                    <>1__state = 4;
                    return true;
                case 4:
                    <>1__state = -1;
                    return false;
            }
        }
</code>

The lambda function is stored as a local variable ''<>8__1'' in the generated IEnumerator class. However, the instance is created at the start of the function, not just before usage, as one might expect.

===== All lambdas are piled into a single DisplayClass anonymous type, and share the same instance. =====

Please fill all the letters into the box to prove you're human. W G V N L Please keep this field empty:

Edit summary

Uninomicon

User Tools

Site Tools

Page Tools