Various fixes.

2017-05-14 20:55:22 +12:00 · 2017-05-14 20:55:22 +12:00 · e652e24cc3
--- a/Common/Internal/Abstraction/ILanguage.cs
+++ b/Common/Internal/Abstraction/ILanguage.cs
@ -1,4 +1,4 @@
-using System.Collections.Immutable;
+using System.Collections.Generic;
 using JetBrains.Annotations;
 using Microsoft.CodeAnalysis;

@ -7,8 +7,7 @@ namespace MirrorSharp.Internal.Abstraction {
        [NotNull] string Name { get; }
        [NotNull] ParseOptions DefaultParseOptions { get; }
        [NotNull] CompilationOptions DefaultCompilationOptions { get; }
-        [NotNull] [ItemNotNull] ImmutableList<MetadataReference> DefaultAssemblyReferences { get; }

-        [NotNull] ILanguageSession CreateSession([NotNull] string text, ParseOptions parseOptions, CompilationOptions compilationOptions, ImmutableList<MetadataReference> metadataReferences);
+        [NotNull] ILanguageSession CreateSession([NotNull] string text, ParseOptions parseOptions, CompilationOptions compilationOptions, [CanBeNull] IReadOnlyCollection<MetadataReference> assemblyReferences);
    }
 }
--- a/Common/Internal/LanguageManager.cs
+++ b/Common/Internal/LanguageManager.cs
@ -26,7 +26,7 @@ namespace MirrorSharp.Internal {

            if (name == "F#") {
                var type = Type.GetType("MirrorSharp.FSharp.FSharpLanguage, MirrorSharp.FSharp", true);
-                return (ILanguage)Activator.CreateInstance(type);
+                return (ILanguage)Activator.CreateInstance(type, nonPublic: true);
            }

            throw new NotSupportedException($"Language '{name}' is not currently supported.");
--- a/Common/Internal/Roslyn/RoslynLanguageBase.cs
+++ b/Common/Internal/Roslyn/RoslynLanguageBase.cs
@ -19,6 +19,7 @@ namespace MirrorSharp.Internal.Roslyn {
        private readonly ImmutableDictionary<string, ImmutableArray<CodeFixProvider>> _defaultCodeFixProvidersIndexedByDiagnosticIds;
        private readonly ImmutableArray<DiagnosticAnalyzer> _defaultAnalyzers;
        private readonly ImmutableList<AnalyzerReference> _defaultAnalyzerReferences;
+        private readonly ImmutableList<MetadataReference> _defaultAssemblyReferences;

        protected RoslynLanguageBase(
            [NotNull] string name,
@ -37,7 +38,7 @@ namespace MirrorSharp.Internal.Roslyn {
            });
            DefaultParseOptions = defaultParseOptions;
            DefaultCompilationOptions = defaultCompilationOptions;
-            DefaultAssemblyReferences = ImmutableList.Create<MetadataReference>(
+            _defaultAssemblyReferences = ImmutableList.Create<MetadataReference>(
                MetadataReference.CreateFromFile(typeof(object).GetTypeInfo().Assembly.Location)
            );
            _defaultAnalyzerReferences = ImmutableList.Create<AnalyzerReference>(
@ -54,15 +55,14 @@ namespace MirrorSharp.Internal.Roslyn {
        public string Name { get; }
        public ParseOptions DefaultParseOptions { get; }
        public CompilationOptions DefaultCompilationOptions { get; }
-        public ImmutableList<MetadataReference> DefaultAssemblyReferences { get; }

-        public ILanguageSession CreateSession(string text, ParseOptions parseOptions, CompilationOptions compilationOptions, ImmutableList<MetadataReference> metadataReferences) {
+        public ILanguageSession CreateSession(string text, ParseOptions parseOptions, CompilationOptions compilationOptions, IReadOnlyCollection<MetadataReference> assemblyReferences) {
            var projectId = ProjectId.CreateNewId();
            var projectInfo = ProjectInfo.Create(
                projectId, VersionStamp.Create(), "_", "_", Name,
                parseOptions: parseOptions,
                compilationOptions: compilationOptions,
-                metadataReferences: metadataReferences,
+                metadataReferences: assemblyReferences ?? _defaultAssemblyReferences,
                analyzerReferences: _defaultAnalyzerReferences
            );
            
--- a/Common/Internal/WorkSession.cs
+++ b/Common/Internal/WorkSession.cs
@ -70,9 +70,8 @@ namespace MirrorSharp.Internal {
            foreach (var change in _compilationOptionsChanges.Values) {
                compilationOptions = change(compilationOptions);
            }
-            var metadataReferences = _options?.GetDefaultMetadataReferencesByLanguageName?.Invoke(Language.Name) ?? Language.DefaultAssemblyReferences;
-
-            _languageSession = Language.CreateSession(_lastText, parseOptions, compilationOptions, metadataReferences);
+            var assemblyReferences = _options?.GetDefaultMetadataReferencesByLanguageName?.Invoke(Language.Name);
+            _languageSession = Language.CreateSession(_lastText, parseOptions, compilationOptions, assemblyReferences);
        }

        public IWorkSessionOptions Options => _options;
--- a/FSharp/FSharp.csproj
+++ b/FSharp/FSharp.csproj
@ -7,6 +7,15 @@
    <TargetFrameworkIdentifier>.NETFramework</TargetFrameworkIdentifier>
    <TargetFrameworkVersion>v4.6</TargetFrameworkVersion>
    <TargetFrameworkProfile />
+    <Version>0.9.0</Version>
+    <GeneratePackageOnBuild>False</GeneratePackageOnBuild>
+    <Authors>Andrey Shchekin</Authors>
+    <Company>Andrey Shchekin</Company>
+    <PackageProjectUrl>https://github.com/ashmind/mirrorsharp</PackageProjectUrl>
+    <RepositoryUrl>https://github.com/ashmind/mirrorsharp.git</RepositoryUrl>
+    <RepositoryType>git</RepositoryType>
+    <PackageTags>F#;CodeMirror</PackageTags>
+    <Description>MirrorSharp F# support library. MirrorSharp is a code editor &lt;textarea&gt; built on Roslyn — see https://github.com/ashmind/mirrorsharp/blob/master/README.md for details.</Description>
  </PropertyGroup>

  <ItemGroup>
--- a/FSharp/FSharpCore.targets
+++ b/FSharp/FSharpCore.targets
@ -0,0 +1,17 @@
+<Project>
+   <!-- Should not be needed once https://github.com/Microsoft/visualfsharp/pull/2884 is available on NuGet -->
+  <Target Name="CopyOptdataAndSigdata" AfterTargets="Build">
+    <ItemGroup>
+      <FSharpCoreReference Include="@(Reference)" Condition="$([System.String]::Copy('%(Reference.Identity)').EndsWith('FSharp.Core.dll'))" />
+    </ItemGroup>
+    <PropertyGroup>
+      <FSharpCorePath>@(FSharpCoreReference->'%(Identity)')</FSharpCorePath>
+      <FSharpCoreDirectoryPath>$([System.IO.Path]::GetDirectoryName($(FSharpCorePath)))</FSharpCoreDirectoryPath>
+    </PropertyGroup>
+    <ItemGroup>
+      <OpdataAndSigdata Include="$(FSharpCoreDirectoryPath)\FSharp.Core.optdata" />
+      <OpdataAndSigdata Include="$(FSharpCoreDirectoryPath)\FSharp.Core.sigdata" />
+    </ItemGroup>
+    <Copy SourceFiles="@(OpdataAndSigdata)" DestinationFolder="$(OutDir)" />
+  </Target>
+</Project>
--- a/FSharp/FSharpLanguage.cs
+++ b/FSharp/FSharpLanguage.cs
@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Linq;
 using System.Reflection;
@ -8,28 +9,31 @@ using Microsoft.FSharp.Core;
 using MirrorSharp.Internal.Abstraction;

 namespace MirrorSharp.FSharp {
-    internal class FSharpLanguage : ILanguage {
+    public class FSharpLanguage : ILanguage {
        public const string Name = "F#";

-        public ParseOptions DefaultParseOptions => null;
-        public CompilationOptions DefaultCompilationOptions => null;
-        public ImmutableList<MetadataReference> DefaultAssemblyReferences { get; }
+        ParseOptions ILanguage.DefaultParseOptions => null;
+        CompilationOptions ILanguage.DefaultCompilationOptions => null;
+        private readonly ImmutableArray<string> _defaultAssemblyReferencePaths;

        static FSharpLanguage() {
            Library.Shim.FileSystem = new RestrictedFileSystem();
        }

-        public FSharpLanguage() {
+        internal FSharpLanguage() {
            var fsharpAssembly = typeof(FSharpOption<>).GetTypeInfo().Assembly;
-            DefaultAssemblyReferences = ImmutableList.Create<MetadataReference>(
+            _defaultAssemblyReferencePaths = ImmutableArray.Create<string>(
                // note: this currently does not work on .NET Core, which is why this project isn't netstandard
-                MetadataReference.CreateFromFile(typeof(object).GetTypeInfo().Assembly.Location),
-                MetadataReference.CreateFromFile(new Uri(fsharpAssembly.EscapedCodeBase).LocalPath)
+                typeof(object).GetTypeInfo().Assembly.Location,
+                new Uri(fsharpAssembly.EscapedCodeBase).LocalPath
            );
        }

-        public ILanguageSession CreateSession(string text, ParseOptions parseOptions, CompilationOptions compilationOptions, ImmutableList<MetadataReference> metadataReferences) {
-            return new FSharpSession(text, metadataReferences);
+        ILanguageSession ILanguage.CreateSession(string text, ParseOptions parseOptions, CompilationOptions compilationOptions, IReadOnlyCollection<MetadataReference> assemblyReferences) {
+            if (assemblyReferences != null)
+                throw new NotSupportedException();
+
+            return new FSharpSession(text, _defaultAssemblyReferencePaths);
        }

        string ILanguage.Name => Name;
--- a/FSharp/FSharpSession.cs
+++ b/FSharp/FSharpSession.cs
@ -18,19 +18,14 @@ namespace MirrorSharp.FSharp {
        private readonly FSharpChecker _checker;
        private readonly FSharpProjectOptions _projectOptions;

-        public FSharpSession(string text, ImmutableList<MetadataReference> metadataReferences) {
+        public FSharpSession(string text, ImmutableArray<string> assemblyReferencePaths) {
            _checker = FSharpChecker.Create(null, null, null, false);
            _text = text;

            var otherOptions = new List<string> { "--noframework" };
-            foreach (var reference in metadataReferences) {
-                switch (reference) {
-                    case PortableExecutableReference pe:
-                        // ReSharper disable once HeapView.ObjectAllocation (Unavoidable? Not worth caching)
-                        otherOptions.Add("-r:" + pe.FilePath);
-                        break;
-                    default: throw new NotSupportedException($"Metadata reference type {reference.GetType()} is not supported.");
-                }
+            foreach (var path in assemblyReferencePaths) {
+                // ReSharper disable once HeapView.ObjectAllocation (Not worth fixing for now)
+                otherOptions.Add("-r:" + path);
            }

            _projectOptions = new FSharpProjectOptions(
@ -52,22 +47,45 @@ namespace MirrorSharp.FSharp {
                _checker.ParseAndCheckFileInProject("_.fs", 0, _text, _projectOptions, null), null, cancellationToken
            ).ConfigureAwait(false);
            var checkSuccess = check as FSharpCheckFileAnswer.Succeeded;
+            var diagnosticCount = parsed.Errors.Length + (checkSuccess?.Item.Errors.Length ?? 0);
+            if (diagnosticCount == 0)
+                return ImmutableArray<Diagnostic>.Empty;

-            var diagnostics = ImmutableArray.CreateBuilder<Diagnostic>(parsed.Errors.Length + (checkSuccess?.Item.Errors.Length ?? 0));
-            ConvertAndAddTo(diagnostics, parsed.Errors);
+            var lineOffsets = MapLineOffsets(_text);
+            var diagnostics = ImmutableArray.CreateBuilder<Diagnostic>(diagnosticCount);
+            ConvertAndAddTo(diagnostics, parsed.Errors, lineOffsets);

            if (checkSuccess != null)
-                ConvertAndAddTo(diagnostics, checkSuccess.Item.Errors);
+                ConvertAndAddTo(diagnostics, checkSuccess.Item.Errors, lineOffsets);

            return diagnostics.MoveToImmutable();
        }

-        private void ConvertAndAddTo(ImmutableArray<Diagnostic>.Builder diagnostics, FSharpErrorInfo[] errors) {
+        private IReadOnlyList<int> MapLineOffsets(string text) {
+            var offsets = new List<int>();
+
+            var previous = '\0';
+            for (var i = 0; i < text.Length; i++) {
+                var @char = text[i];
+                if (previous == '\n' || (previous == '\r' && @char != '\n'))
+                    offsets.Add(i);
+                previous = @char;
+            }
+
+            return offsets;
+        }
+
+        private void ConvertAndAddTo(ImmutableArray<Diagnostic>.Builder diagnostics, FSharpErrorInfo[] errors, IReadOnlyList<int> lineOffsets) {
            foreach (var error in errors) {
                var severity = ConvertToDiagnosticSeverity(error.Severity);
+
+                var startOffset = GetOffset(error.StartLineAlternate, error.StartColumn, lineOffsets);
                var location = Location.Create(
                    "",
-                    new TextSpan(0, 0),
+                    new TextSpan(
+                        startOffset,
+                        GetOffset(error.EndLineAlternate, error.EndColumn, lineOffsets) - startOffset
+                    ),
                    new LinePositionSpan(
                        new LinePosition(error.StartLineAlternate, error.StartColumn),
                        new LinePosition(error.EndLineAlternate, error.EndColumn)
@ -79,12 +97,17 @@ namespace MirrorSharp.FSharp {
                    error.Message,
                    severity, severity,
                    isEnabledByDefault: false,
-                    warningLevel: 0,
+                    warningLevel: severity == DiagnosticSeverity.Warning ? 1 : 0,
                    location: location
                ));
            }
        }

+        private int GetOffset(int line, int column, IReadOnlyList<int> lineOffsets) {
+            var lineOffset = line > 1 ? lineOffsets[line - 2] : 0;
+            return lineOffset + column;
+        }
+
        private DiagnosticSeverity ConvertToDiagnosticSeverity(FSharpErrorSeverity errorSeverity) {
            return Equals(errorSeverity, FSharpErrorSeverity.Error) ? DiagnosticSeverity.Error : DiagnosticSeverity.Warning;
        }
--- a/MirrorSharp.sln
+++ b/MirrorSharp.sln
@ -11,8 +11,6 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "AspNetCore", "AspNetCore\As
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Owin", "Owin\Owin.csproj", "{00CC1A50-B233-4045-9540-CB2316808C1B}"
 EndProject
-Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Owin.Demo", "Owin.Demo\Owin.Demo.csproj", "{D2EB1CDD-12B5-4FDC-A56C-8A327200E759}"
-EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "WebAssets", "WebAssets\WebAssets.csproj", "{FF13139E-69D3-472E-B4FE-AC2623AD67B9}"
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Benchmarks", "Benchmarks\Benchmarks.csproj", "{35D73C72-267B-4598-ABC0-F1E1BACDE451}"
@ -27,6 +25,8 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "FSharp", "FSharp\FSharp.csp
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Tests.Roslyn2.Net46", "Tests.Roslyn2.Net46\Tests.Roslyn2.Net46.csproj", "{7F531F1E-5AF6-4FC6-BF71-84EB00C1B1EC}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Owin.Demo", "Owin.Demo\Owin.Demo.csproj", "{3C2A0FC7-4485-4654-B3B2-5717A2F2C97A}"
+EndProject
 Global
 	GlobalSection(SharedMSBuildProjectFiles) = preSolution
 		Tests.Shared\MirrorSharp.Tests.Shared.projitems*{0a9078a1-bd26-4dc7-87bb-ded125f6218b}*SharedItemsImports = 13
@ -52,10 +52,6 @@ Global
 		{00CC1A50-B233-4045-9540-CB2316808C1B}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{00CC1A50-B233-4045-9540-CB2316808C1B}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{00CC1A50-B233-4045-9540-CB2316808C1B}.Release|Any CPU.Build.0 = Release|Any CPU
-		{D2EB1CDD-12B5-4FDC-A56C-8A327200E759}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{D2EB1CDD-12B5-4FDC-A56C-8A327200E759}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{D2EB1CDD-12B5-4FDC-A56C-8A327200E759}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{D2EB1CDD-12B5-4FDC-A56C-8A327200E759}.Release|Any CPU.Build.0 = Release|Any CPU
 		{FF13139E-69D3-472E-B4FE-AC2623AD67B9}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{FF13139E-69D3-472E-B4FE-AC2623AD67B9}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{35D73C72-267B-4598-ABC0-F1E1BACDE451}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
@ -78,6 +74,10 @@ Global
 		{7F531F1E-5AF6-4FC6-BF71-84EB00C1B1EC}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{7F531F1E-5AF6-4FC6-BF71-84EB00C1B1EC}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{7F531F1E-5AF6-4FC6-BF71-84EB00C1B1EC}.Release|Any CPU.Build.0 = Release|Any CPU
+		{3C2A0FC7-4485-4654-B3B2-5717A2F2C97A}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{3C2A0FC7-4485-4654-B3B2-5717A2F2C97A}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{3C2A0FC7-4485-4654-B3B2-5717A2F2C97A}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{3C2A0FC7-4485-4654-B3B2-5717A2F2C97A}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
--- a/Owin.Demo/Owin.Demo.csproj
+++ b/Owin.Demo/Owin.Demo.csproj
@ -22,7 +22,9 @@
  </ItemGroup>

  <ItemGroup>
+    <ProjectReference Include="..\FSharp\FSharp.csproj" />
    <ProjectReference Include="..\Owin\Owin.csproj" />
  </ItemGroup>
  
+  <Import Project="../FSharp/FSharpCore.targets" />
 </Project>
--- a/Owin.Demo/Startup.cs
+++ b/Owin.Demo/Startup.cs
@ -1,4 +1,6 @@
-using Microsoft.Owin;
+using Microsoft.CodeAnalysis;
+using Microsoft.Owin;
+using MirrorSharp.FSharp;
 using MirrorSharp.Owin.Demo;
 using Owin;

@ -10,6 +12,7 @@ namespace MirrorSharp.Owin.Demo {
            app.UseDefaultFiles()
               .UseStaticFiles()
               .UseMirrorSharp(new MirrorSharpOptions {
+                   LanguageNames = { LanguageNames.CSharp, FSharpLanguage.Name },
                   SelfDebugEnabled = true,
                   IncludeExceptionDetails = true
               });
--- a/Owin.Demo/Web.config
+++ b/Owin.Demo/Web.config
@ -19,7 +19,19 @@
  </system.webServer>
  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
-      <probing privatePath="bin\Debug\net45"/>
+      <probing privatePath="bin\Debug\net46"/>
+      <dependentAssembly>
+        <assemblyIdentity name="System.Collections.Immutable" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
+        <bindingRedirect oldVersion="1.2.0.0" newVersion="1.2.1.0"/>
+      </dependentAssembly>
+      <dependentAssembly>
+        <assemblyIdentity name="System.IO.FileSystem" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
+        <bindingRedirect oldVersion="4.0.1.0" newVersion="4.0.2.0"/>
+      </dependentAssembly>
+      <dependentAssembly>
+        <assemblyIdentity name="FSharp.Core" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
+        <bindingRedirect oldVersion="4.4.0.0" newVersion="4.4.1.0"/>
+      </dependentAssembly>
    </assemblyBinding>
  </runtime>
 </configuration>
--- a/Owin.Demo/index.html
+++ b/Owin.Demo/index.html
@ -1,30 +1,52 @@
 <!DOCTYPE html>
 <html>
  <head>
-    <meta charset="utf-8" />
+    <meta charset="utf-8">
    <title>MirrorSharp Demo</title>
-    <link rel="stylesheet" href="bower_components/codemirror/lib/codemirror.css" />
-    <link rel="stylesheet" href="bower_components/codemirror/addon/lint/lint.css" />
-    <link rel="stylesheet" href="bower_components/codemirror/addon/hint/show-hint.css" />
-    <link rel="stylesheet" href="bower_components/codemirror-addon-lint-fix/dist/lint-fix.css" />
-    <link rel="stylesheet" href="bower_components/mirrorsharp/mirrorsharp.css" />
+    <link rel="stylesheet" href="bower_components/codemirror/lib/codemirror.css">
+    <link rel="stylesheet" href="bower_components/codemirror/addon/lint/lint.css">
+    <link rel="stylesheet" href="bower_components/codemirror/addon/hint/show-hint.css">
+    <link rel="stylesheet" href="bower_components/codemirror-addon-lint-fix/dist/lint-fix.css">
+    <link rel="stylesheet" href="bower_components/mirrorsharp/mirrorsharp.css">
+    <link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Open+Sans">
    <style>
+      * { box-sizing: border-box; }
      html, body { width: 100%; height: 100%; }
-      body { padding: 0; margin: 0; font-size: 16px; }
+      body {
+        padding: 0;
+        margin: 0;
+        font-size: 16px;
+        display: flex;
+        flex-direction: column;
+        padding: 10px;
+      }
+      nav { display: flex; font-family: 'Open Sans', sans-serif; }
+      ul {
+        list-style: none;
+        display: flex;
+        padding: 0;
+        margin: 0;
+      }
+      li {
+        margin-left: 10px;
+      }
+      a { text-decoration: none; }
+      a:hover { text-decoration: underline; }
      .CodeMirror {
-        position: absolute;
-        top: 0;
-        bottom: 0;
-        left: 0;
-        right: 0;
-        margin: 10px;
-        height: auto;
-        box-sizing: border-box;
+        flex-grow: 1;
+        margin-top: 10px;
        border: 1px solid #ddd;
      }
    </style>
  </head>
  <body>
+    <nav>
+      Language:
+      <ul>
+        <li><a href="index.html?language=CSharp">C#</a></li>
+        <li><a href="index.html?language=FSharp">F#</a></li>
+      </ul>
+    </nav>
    <textarea>using System;
 class C {
    void M() {
@ -33,14 +55,22 @@ class C {

    <script src="bower_components/codemirror/lib/codemirror.js"></script>
    <script src="bower_components/codemirror/mode/clike/clike.js"></script>
+    <script src="bower_components/codemirror/mode/mllike/mllike.js"></script>
    <script src="bower_components/codemirror/addon/lint/lint.js"></script>
    <script src="bower_components/codemirror/addon/hint/show-hint.js"></script>
    <script src="bower_components/codemirror-addon-lint-fix/dist/lint-fix.js"></script>
    <script src="bower_components/mirrorsharp/mirrorsharp.js"></script>
    <script>
-      mirrorsharp(document.getElementsByTagName('textarea')[0], {
-        serviceUrl: window.location.href.replace(/^http(.+)\/?$/i, 'ws$1/mirrorsharp'),
-        selfDebugEnabled: true
+      'use strict';
+      const language = (window.location.search.match(/language=([^&]+)/)[1] || ['C#']).replace('Sharp', '#');
+      const textarea = document.getElementsByTagName('textarea')[0];
+      if (language === 'F#')
+        textarea.value = '1 |> ignore';
+
+      mirrorsharp(textarea, {
+        serviceUrl: window.location.href.replace(/^http(s?:\/\/[^/]+).*$/i, 'ws$1/mirrorsharp'),
+        selfDebugEnabled: true,
+        language: (window.location.search.match(/language=([^&]+)/)[1] || ['C#']).replace('Sharp', '#')
      });
    </script>
  </body>
--- a/Testing/MirrorSharpTestDriver.cs
+++ b/Testing/MirrorSharpTestDriver.cs
@ -68,11 +68,21 @@ namespace MirrorSharp.Testing {
            return SendAsync<SlowUpdateResult<TExtensionResult>>(CommandIds.SlowUpdate);
        }

+        [PublicAPI]
+        public Task<OptionsEchoResult> SendSetOptionAsync(string name, string value) {
+            return SendAsync<OptionsEchoResult>(CommandIds.SetOptions, $"{name}={value}");
+        }
+
        [PublicAPI]
        public Task<OptionsEchoResult> SendSetOptionsAsync(IDictionary<string, string> options) {
            return SendAsync<OptionsEchoResult>(CommandIds.SetOptions, string.Join(",", options.Select(o => $"{o.Key}={o.Value}")));
        }

+        [PublicAPI]
+        internal Task SendReplaceTextAsync(string newText, int start = 0, int length = 0, int newCursorPosition = 0, string reason = "") {
+            return SendAsync(CommandIds.ReplaceText, $"{start}:{length}:{newCursorPosition}:{reason}:{newText}");
+        }
+
        internal async Task<TResult> SendAsync<TResult>(char commandId, HandlerTestArgument argument = null)
            where TResult : class
        {
--- a/Testing/Results/ResultSpan.cs
+++ b/Testing/Results/ResultSpan.cs
@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+// ReSharper disable ClassNeverInstantiated.Global
+// ReSharper disable CollectionNeverUpdated.Global
+// ReSharper disable UnusedAutoPropertyAccessor.Global
+
+namespace MirrorSharp.Testing.Results {
+    public class ResultSpan {
+        public int Start { get; set; }
+        public int Length { get; set; }
+    }
+}
--- a/Testing/Results/SlowUpdateDiagnostic.cs
+++ b/Testing/Results/SlowUpdateDiagnostic.cs
@ -10,6 +10,7 @@ namespace MirrorSharp.Testing.Results {
        [CanBeNull] public string Id { get; set; }
        [CanBeNull] public string Message { get; set; }
        [CanBeNull] public string Severity { get; set; }
+        [CanBeNull] public ResultSpan Span { get; set; }
        [NotNull] public IList<string> Tags { get; } = new List<string>();
        [NotNull] public IList<SlowUpdateDiagnosticAction> Actions { get; } = new List<SlowUpdateDiagnosticAction>();

--- a/Tests.Roslyn2.Net46/FSharpTests.cs
+++ b/Tests.Roslyn2.Net46/FSharpTests.cs
@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using System.Linq;
 using MirrorSharp.Internal;
 using MirrorSharp.Testing;
 using Xunit;
@ -8,19 +9,42 @@ namespace MirrorSharp.Tests {

    public class FSharpTests {
        [Fact]
-        public async void Prototype() {
+        public async void SlowUpdate_ProducesNoDiagnostics_IfCodeIsValid() {
            var driver = MirrorSharpTestDriver.New();
-            await driver.SendSetOptionsAsync(new Dictionary<string, string> {{ "language", "F#" }});
-            var code = @"open System
+            await driver.SendSetOptionAsync("language", "F#");
+            var code = @"
+                open System

-[<EntryPoint>]
-let main argv = 
-    printfn ""Hello World""
-    Console.ReadLine() |> ignore
-    0";
-            await driver.SendAsync(ReplaceText, $"0:0:0::{code}");
+                [<EntryPoint>]
+                let main argv = 
+                    printfn ""Hello World""
+                    Console.ReadLine() |> ignore
+                    0
+            ".Trim().Replace("                ", "");
+            await driver.SendReplaceTextAsync(code);
            var result = await driver.SendSlowUpdateAsync();
            Assert.Empty(result.Diagnostics);
        }
+
+        [Fact]
+        public async void SlowUpdate_ProducesExpectedDiagnostics_IfCodeHasErrors() {
+            var driver = MirrorSharpTestDriver.New();
+            await driver.SendSetOptionAsync("language", "F#");
+            await driver.SendReplaceTextAsync("xyz");
+            var result = await driver.SendSlowUpdateAsync();
+            
+            Assert.Equal(
+                new[] { new {
+                    Severity = "error",
+                    Message = "The value or constructor 'xyz' is not defined.",
+                    Span = new { Start = (int?)0, Length = (int?)3 }
+                } },
+                result.Diagnostics.Select(d => new {
+                    d.Severity,
+                    d.Message,
+                    Span = new { d.Span?.Start, d.Span?.Length }
+                }).ToArray()
+            );
+        }
    }
 }
--- a/Tests.Roslyn2.Net46/Tests.Roslyn2.Net46.csproj
+++ b/Tests.Roslyn2.Net46/Tests.Roslyn2.Net46.csproj
@ -27,19 +27,5 @@
    <ProjectReference Include="..\Testing\Testing.csproj" />
  </ItemGroup>
  
-  <!-- Should not be needed once https://github.com/Microsoft/visualfsharp/pull/2884 is available on NuGet -->
-  <Target Name="CopyOptdataAndSigdata" AfterTargets="Build">
-    <ItemGroup>
-      <FSharpCoreReference Include="@(Reference)" Condition="$([System.String]::Copy('%(Reference.Identity)').EndsWith('FSharp.Core.dll'))" />
-    </ItemGroup>
-    <PropertyGroup>
-      <FSharpCorePath>@(FSharpCoreReference->'%(Identity)')</FSharpCorePath>
-      <FSharpCoreDirectoryPath>$([System.IO.Path]::GetDirectoryName($(FSharpCorePath)))</FSharpCoreDirectoryPath>
-    </PropertyGroup>
-    <ItemGroup>
-      <OpdataAndSigdata Include="$(FSharpCoreDirectoryPath)\FSharp.Core.optdata" />
-      <OpdataAndSigdata Include="$(FSharpCoreDirectoryPath)\FSharp.Core.sigdata" />
-    </ItemGroup>
-    <Copy SourceFiles="@(OpdataAndSigdata)" DestinationFolder="$(OutDir)" />
-  </Target>
+  <Import Project="../FSharp/FSharpCore.targets" />
 </Project>
--- a/WebAssets/mirrorsharp.js
+++ b/WebAssets/mirrorsharp.js
@ -1,4 +1,4 @@
-/* globals console:false, CloseEvent:false */
+/* globals console:false, CloseEvent:false */
 (function (root, factory) {
    'use strict';
    // ReSharper disable UndeclaredGlobalVariableUsing (R# bug, https://youtrack.jetbrains.com/issue/RSRP-462411)
@ -434,7 +434,8 @@
        const defaultLanguage = 'C#';
        const languageModes = {
            'C#': 'text/x-csharp',
-            'Visual Basic': 'text/x-vb'
+            'Visual Basic': 'text/x-vb',
+            'F#': 'text/x-fsharp'
        };

        var language;
--- a/WebAssets/package.json
+++ b/WebAssets/package.json
@ -1,6 +1,6 @@
 {
  "name": "mirrorsharp",
-  "version": "0.9.0-pre-20170501",
+  "version": "0.9.0-pre-20170517",
  "description": "A code editor `<textarea>` for .NET.",
  "authors": [
    "Andrey Shchekin (https://github.com/ashmind)"