Differences

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--- ienumerator [2021/03/18 01:18] – 73.95.178.156
+++ ienumerator [2025/01/15 04:35] (current) – external edit 127.0.0.1
@@ Line 2: / Line 2: @@
 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 =====
@@ Line 61: / Line 86: @@
 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.**