New tests.

[mono.git] / mcs / docs / new-anonymous-design.txt

diff --git a/mcs/docs/new-anonymous-design.txt b/mcs/docs/new-anonymous-design.txt
index 402654b5f82d443774aeca791410dc888d35aba6..5ceeee6c09aae51b9863ac60c227366dd3d9765d 100644 (file)
--- a/mcs/docs/new-anonymous-design.txt
+++ b/mcs/docs/new-anonymous-design.txt
@@ -99,17 +99,34 @@ The new code fundamentally changes the concept of CaptureContexts and
 ScopeInfos.  CaptureContext is completely gone while the ScopeInfo has
 been completely redesigned.
 
-Each method containing anonymous methods introduces a "root scope" in
-which all other scopes are nested.  This root scope is also called the
-anonymous method's host (class `AnonymousMethodHost' in anonymous.cs).
+Unfortunately, computing the "root scope" of an anonymous method is
+very difficult and was the primary reason for the update in late
+November 2006.  Consider the following example:
+
+       ====
+       TestDelegate d = null;
+       for (int i = 1; i <= 5; i++) {
+               int k = i;
+               TestDelegate temp = delegate {
+                       Console.WriteLine ("i = {0}, k = {1}", i, k);
+                       sum_i += 1 << i;
+                       sum_k += 1 << k;
+               };
+               temp ();
+               d += temp;
+       }
+       ====
+
+Note that we're instantiating the same anonymous method multiple times
+inside a loop.  The important thing is that each instantiation must
+get the current version of `k'; ie. we must create a new instance 'k's
+helper-class for each instantiation.  They all share `i's helper-class.
 
-The root scope deals with everything related to generics and also
-hosts the parameters and `this'.  All other scopes are nested inside
-the root scope.
+This means that the anonymous method needs to be hosted in the inner
+helper-class.
 
-Note that if you have child scopes, they're all nested directly inside
-the root scope, not inside each other.  Because of that, we don't need
-to link / reparent them.
+Because of that, we need to compute all the scopes before actually
+creating the anonymous method.
 
 Anonymous Methods and Generics:
 -------------------------------