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ienumerator [2021/03/18 01:18]
73.95.178.156 		ienumerator [2021/04/29 19:10] (current)
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 Notes on the underlying implementation of C# generators (which are used in Unity for coroutines). Notes on the underlying implementation of C# generators (which are used in Unity for coroutines).
 +
 +You can use SharpLab to view the decompiled C# from a simple generator, to help understand the transformation that is happening. Both .NET and Mono do seem to use the same compiler transformation when turning Generators into anonymous IEnumerator classes. [[https://sharplab.io/#v2:EYLgtghgzgLgpgJwDQBMQGoA+ABATARgFgAobABgAJt8A6AYQHsAbJuAYxgEsGA7KAbhLYAzFVwU6FAN4kKcigHoFIipx4wKAD0HF5FWft3yVASQCiPAK5hEEGAwQUAsgAoAlNIN651fFQDsFPg63sb4ftiBuCGhVOEBFMIxob4JACzJFAC+XoZ6phbWtvaOACpwsC7YAKwAPMAMzAB8FABmljxsHjJGKfGRbR1s7pk5xFlAA===|example]]
 +
 +===== States =====
 +
 +Generators are compiled down into a state machine, with states for each ''yield return'' point. ie:
 +  * 0: The generator has not yet been run.
 +  * 1: The generator has paused on the first yield return.
 +  * 2: The generator has paused on the second yield return.
 +  * -1: The generator has finished, the generator exited early, or the generator threw an exception.
 +
 +The state value is set in a field ''%%private int <>1__state%%'' on the generated IEnumerator class:
 +
 +<code c#>
 +    [CompilerGenerated]
 +    private sealed class <M>d__0 : IEnumerator<object>, IDisposable, IEnumerator
 +    {
 +        private int <>1__state;
 +
 +        private object <>2__current;
 +
 +        public C <>4__this;
 +        // snipped
 +</code>
 +
  
 ===== Lambda function DisplayClass classes are initialized at the start of the function ===== ===== Lambda function DisplayClass classes are initialized at the start of the function =====
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 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.  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. =====+**All lambdas are piled into a single DisplayClass anonymous type, and share the same instance.**
  
  
ienumerator.1616030329.txt.gz ยท Last modified: 2021/03/18 01:18 by 73.95.178.156

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