[dotnet] Start to stub in the bits we'll need to implement .leave.

dotnet/compiler/PAST2DNSTCompiler.pm

@@ -140,9 +140,10 @@ method compile(PAST::Node $node) {
     return DNST::CompilationUnit.new(
         DNST::Using.new( :namespace('System') ),
         DNST::Using.new( :namespace('System.Collections.Generic') ),
-        DNST::Using.new( :namespace('Rakudo.Runtime') ),
         DNST::Using.new( :namespace('Rakudo.Metamodel') ),
         DNST::Using.new( :namespace('Rakudo.Metamodel.Representations') ),
+        DNST::Using.new( :namespace('Rakudo.Runtime') ),
+        DNST::Using.new( :namespace('Rakudo.Runtime.Exceptions') ),
         $class
     );
 }
@@ -357,7 +358,20 @@ our multi sub dnst_for(PAST::Block $block) {
     ));
     $result.push(DNST::Bind.new( 'TC.CurrentContext', 'C' ));
     $result.push(DNST::TryFinally.new(
-        $stmts,
+        DNST::TryCatch.new(
+            :exception_type('LeaveStackUnwinderException'),
+            :exception_var('exc'),
+            $stmts,
+            DNST::Stmts.new(
+                DNST::If.new(
+                    DNST::Literal.new(
+                        :value("(exc.TargetBlock == StaticBlockInfo[$our_sbi] ? 1 : 0)")
+                    ),
+                    DNST::Throw.new()
+                ),
+                "exc.PayLoad"
+            )
+        ),
         DNST::Bind.new( 'TC.CurrentContext', 'C.Caller' )
     ));
 

dotnet/runtime/Rakudo.Net.csproj

@@ -45,6 +45,8 @@
     <Reference Include="System.Core">
       <RequiredTargetFramework>3.5</RequiredTargetFramework>
     </Reference>
+    <Reference Include="System.Data" />
+    <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup>
     <Compile Include="Init.cs" />
@@ -57,6 +59,7 @@
     <Compile Include="Metamodel\Representations\RakudoCodeRef.cs" />
     <Compile Include="Metamodel\REPRRegistry.cs" />
     <Compile Include="Runtime\Context.cs" />
+    <Compile Include="Runtime\Exceptions\LeaveStackUnwinderException.cs" />
     <Compile Include="Runtime\ExecutionDomain.cs" />
     <Compile Include="Metamodel\KnowHOW\KnowHOWBootstrapper.cs" />
     <Compile Include="Metamodel\KnowHOW\KnowHOWREPR.cs" />

dotnet/runtime/Runtime/Exceptions/LeaveStackUnwinderException.cs

@@ -0,0 +1,36 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using Rakudo.Metamodel;
+using Rakudo.Metamodel.Representations;
+
+namespace Rakudo.Runtime.Exceptions
+{
+    /// <summary>
+    /// This exception is thrown to actually unwind the (dotnet) stack after
+    /// we run an exception handler.
+    /// </summary>
+    public class LeaveStackUnwinderException : Exception
+    {
+        /// <summary>
+        /// The block we're looking for.
+        /// </summary>
+        public RakudoCodeRef.Instance TargetBlock;
+
+        /// <summary>
+        /// The value to exit with.
+        /// </summary>
+        public RakudoObject PayLoad;
+
+        /// <summary>
+        /// Creates a LeaveStackUnwinderException to 
+        /// </summary>
+        /// <param name="TargetBlock"></param>
+        public LeaveStackUnwinderException(RakudoCodeRef.Instance TargetBlock, RakudoObject PayLoad)
+        {
+            this.TargetBlock = TargetBlock;
+            this.PayLoad = PayLoad;
+        }
+    }
+}