Tidy up return flow (#12)

.gitignore

@@ -7,3 +7,6 @@ riderModule.iml
 .direnv/
 *.DotSettings.user
 result
+
+.fake
+.vscode/

WoofWare.PawPrint.Test/Roslyn.fs

@@ -13,7 +13,7 @@ module Roslyn =
     let compile (sources : string list) : byte[] =
         // Create a syntax tree per source snippet.
         let parseOptions =
-            CSharpParseOptions.Default.WithLanguageVersion (LanguageVersion.Preview)
+            CSharpParseOptions.Default.WithLanguageVersion LanguageVersion.Preview
 
         let syntaxTrees : SyntaxTree[] =
             sources
@@ -25,14 +25,13 @@ module Roslyn =
 
         // Reference every assembly found in the runtime directory – crude but
         // guarantees we can resolve System.* et al.
-        let runtimeDir =
+        let runtimeDir = Runtime.InteropServices.RuntimeEnvironment.GetRuntimeDirectory ()
-            System.Runtime.InteropServices.RuntimeEnvironment.GetRuntimeDirectory ()
 
         let metadataReferences : MetadataReference[] =
             Directory.GetFiles (runtimeDir, "*.dll")
             |> Array.map (fun path -> MetadataReference.CreateFromFile path :> MetadataReference)
 
-        let compilationOptions = CSharpCompilationOptions (OutputKind.ConsoleApplication)
+        let compilationOptions = CSharpCompilationOptions OutputKind.ConsoleApplication
 
         let compilation =
             CSharpCompilation.Create (
@@ -44,7 +43,7 @@ module Roslyn =
 
         use peStream = new MemoryStream ()
 
-        let emitResult = compilation.Emit (peStream)
+        let emitResult = compilation.Emit peStream
 
         if emitResult.Success then
             peStream.ToArray ()

WoofWare.PawPrint.Test/TestCases.fs

@@ -12,6 +12,22 @@ open WoofWare.PawPrint.Test
 module TestCases =
     let assy = typeof<RunResult>.Assembly
 
+    let unimplemented =
+        [
+            {
+                FileName = "BasicException.cs"
+                ExpectedReturnCode = 10
+            }
+            {
+                FileName = "WriteLine.cs"
+                ExpectedReturnCode = 10
+            }
+            {
+                FileName = "BasicLock.cs"
+                ExpectedReturnCode = 10
+            }
+        ]
+
     let cases : TestCase list =
         [
             {
@@ -25,7 +41,7 @@ module TestCases =
         ]
 
     [<TestCaseSource(nameof cases)>]
-    let ``Can run a no-op`` (case : TestCase) : unit =
+    let ``Can evaluate C# files`` (case : TestCase) : unit =
         let source = Assembly.getEmbeddedResourceAsString case.FileName assy
         let image = Roslyn.compile [ source ]
         let messages, loggerFactory = LoggerFactory.makeTest ()
@@ -35,15 +51,54 @@ module TestCases =
 
         use peImage = new MemoryStream (image)
 
-        let terminalState, terminatingThread =
+        try
-            Program.run loggerFactory peImage dotnetRuntimes []
+            let terminalState, terminatingThread =
+                Program.run loggerFactory peImage dotnetRuntimes []
 
-        let exitCode =
+            let exitCode =
-            match terminalState.ThreadState.[terminatingThread].MethodState.EvaluationStack.Values with
+                match terminalState.ThreadState.[terminatingThread].MethodState.EvaluationStack.Values with
-            | [] -> failwith "expected program to return a value, but it returned void"
+                | [] -> failwith "expected program to return a value, but it returned void"
-            | head :: _ ->
+                | head :: _ ->
-                match head with
+                    match head with
-                | EvalStackValue.Int32 i -> i
+                    | EvalStackValue.Int32 i -> i
-                | ret -> failwith "expected program to return an int, but it returned %O{ret}"
+                    | ret -> failwith $"expected program to return an int, but it returned %O{ret}"
 
-        exitCode |> shouldEqual case.ExpectedReturnCode
+            exitCode |> shouldEqual case.ExpectedReturnCode
+
+        with _ ->
+            for message in messages () do
+                System.Console.Error.WriteLine $"{message}"
+
+            reraise ()
+
+    [<TestCaseSource(nameof unimplemented)>]
+    [<Explicit "not yet implemented">]
+    let ``Can evaluate C# files (unimplemented)`` (case : TestCase) : unit =
+        let source = Assembly.getEmbeddedResourceAsString case.FileName assy
+        let image = Roslyn.compile [ source ]
+        let messages, loggerFactory = LoggerFactory.makeTest ()
+
+        let dotnetRuntimes =
+            DotnetRuntime.SelectForDll assy.Location |> ImmutableArray.CreateRange
+
+        use peImage = new MemoryStream (image)
+
+        try
+            let terminalState, terminatingThread =
+                Program.run loggerFactory peImage dotnetRuntimes []
+
+            let exitCode =
+                match terminalState.ThreadState.[terminatingThread].MethodState.EvaluationStack.Values with
+                | [] -> failwith "expected program to return a value, but it returned void"
+                | head :: _ ->
+                    match head with
+                    | EvalStackValue.Int32 i -> i
+                    | ret -> failwith $"expected program to return an int, but it returned %O{ret}"
+
+            exitCode |> shouldEqual case.ExpectedReturnCode
+
+        with _ ->
+            for message in messages () do
+                System.Console.Error.WriteLine $"{message}"
+
+            reraise ()

WoofWare.PawPrint.Test/WoofWare.PawPrint.Test.fsproj

@@ -19,8 +19,9 @@
     <Compile Include="TestBasicLock.fs" />
     <EmbeddedResource Include="sources\BasicLock.cs" />
     <EmbeddedResource Include="sources\NoOp.cs" />
-    <EmbeddedResource Include="sources\HelloWorld.cs" />
+    <EmbeddedResource Include="sources\BasicException.cs" />
     <EmbeddedResource Include="sources\TriangleNumber.cs" />
+    <EmbeddedResource Include="sources\WriteLine.cs" />
   </ItemGroup>
 
   <ItemGroup>

WoofWare.PawPrint.Test/sources/BasicException.cs

@@ -6,7 +6,6 @@ namespace HelloWorldApp
     {
         static int ReallyMain(string[] args)
         {
-            Console.WriteLine("Hello, world!");
             return 0;
         }
 

WoofWare.PawPrint.Test/sources/WriteLine.cs

@@ -0,0 +1,13 @@
+using System;
+
+namespace HelloWorldApp
+{
+    class Program
+    {
+        static int Main(string[] args)
+        {
+            Console.WriteLine("Hello, world!");
+            return 0;
+        }
+    }
+}

WoofWare.PawPrint/AbstractMachine.fs

@@ -781,25 +781,6 @@ module IlMachineState =
                     )
         }
 
-    // TODO: which stack do we actually want to push to?
-    let pushToStackCoerced (o : EvalStackValue) (targetType : TypeDefn) (thread : ThreadId) (state : IlMachineState) =
-        { state with
-            ThreadState =
-                state.ThreadState
-                |> Map.change
-                    thread
-                    (fun threadState ->
-                        match threadState with
-                        | None -> failwith "Logic error: tried to push to stack of a nonexistent thread"
-                        | Some threadState ->
-                            { threadState with
-                                ThreadState.MethodState =
-                                    threadState.MethodState |> MethodState.pushToEvalStack (failwith "TODO")
-                            }
-                            |> Some
-                    )
-        }
-
     let popFromStackToLocalVariable
         (thread : ThreadId)
         (localVariableIndex : int)
@@ -1018,26 +999,27 @@ module AbstractMachine =
 
             let state =
                 match returnState.WasConstructingObj with
-                | None -> state
                 | Some constructing ->
+                    // Assumption: a constructor can't also return a value.
                     state
                     |> IlMachineState.pushToEvalStack (CliType.OfManagedObject constructing) currentThread
+                | None ->
+                    match threadStateAtEndOfMethod.MethodState.EvaluationStack.Values with
+                    | [] ->
+                        // no return value
+                        state
+                    | [ retVal ] ->
+                        let retType =
+                            threadStateAtEndOfMethod.MethodState.ExecutingMethod.Signature.ReturnType
 
-            match threadStateAtEndOfMethod.MethodState.EvaluationStack.Values with
+                        let toPush = EvalStackValue.toCliTypeCoerced (CliType.zeroOf retType) retVal
-            | [] ->
-                // no return value
-                (state, WhatWeDid.Executed) |> ExecutionResult.Stepped
-            | [ retVal ] ->
-                let retType =
-                    threadStateAtEndOfMethod.MethodState.ExecutingMethod.Signature.ReturnType
 
-                state
+                        state |> IlMachineState.pushToEvalStack toPush currentThread
-                |> IlMachineState.pushToStackCoerced retVal retType currentThread
+                    | _ ->
-                |> Tuple.withRight WhatWeDid.Executed
+                        failwith
-                |> ExecutionResult.Stepped
+                            "Unexpected interpretation result has a local evaluation stack with more than one element on RET"
-            | _ ->
+
-                failwith
+            state |> Tuple.withRight WhatWeDid.Executed |> ExecutionResult.Stepped
-                    "Unexpected interpretation result has a local evaluation stack with more than one element on RET"
 
         | LdcI4_0 ->
             state