Formatter self registration and tabular data improvements (#1346)

* use FormatContext for formatter recursion counting

* dispose writer when FormatContext owns it

* add constructor for delegate that returns string, for parity with PlainTextFormatter<T>

* ITypeFormatterSource / TypeFormatterSourceAttribute

* refactor tabular data, add a lazy formatter for it

* allow first field to be null and still correctly infer tabular data column type; misc refactoring

.gitignore

@@ -49,6 +49,9 @@ Generated\ Files/
 *.VisualState.xml
 TestResult.xml
 
+# Assent / ApprovalTests
+*.received.json
+
 # Build Results of an ATL Project
 [Dd]ebugPS/
 [Rr]eleasePS/

dotnet-interactive.v3.ncrunchsolution

@@ -1,6 +1,5 @@
 <SolutionConfiguration>
   <Settings>
-    <AllowParallelTestExecution>True</AllowParallelTestExecution>
     <SolutionConfigured>True</SolutionConfigured>
   </Settings>
 </SolutionConfiguration>

src/Microsoft.DotNet.Interactive.ExtensionLab.Tests/DataFrameKernelExtensionTests.cs

@@ -9,7 +9,7 @@
 
 using Microsoft.Data.Analysis;
 using Microsoft.DotNet.Interactive.Formatting;
-
+using Microsoft.DotNet.Interactive.Formatting.TabularData;
 using Xunit;
 
 namespace Microsoft.DotNet.Interactive.ExtensionLab.Tests

src/Microsoft.DotNet.Interactive.ExtensionLab/DataFrameKernelExtension.cs

@@ -16,6 +16,7 @@
 using Microsoft.DotNet.Interactive.CSharp;
 using Microsoft.DotNet.Interactive.ExtensionLab;
 using Microsoft.DotNet.Interactive.Formatting;
+using Microsoft.DotNet.Interactive.Formatting.TabularData;
 using Microsoft.ML;
 
 namespace Microsoft.DotNet.Interactive.ExtensionLab
@@ -217,7 +218,7 @@ public static TabularDataResource ToTabularDataResource(this IDataView source)
         public static TabularDataResourceJsonString ToTabularJsonString(this IDataView source)
         {
             var tabularDataResource = source.ToTabularDataResource();
-            return tabularDataResource.ToJson();
+            return tabularDataResource.ToJsonString();
         }
     }
 }

src/Microsoft.DotNet.Interactive.ExtensionLab/NteractDataExplorer.cs

@@ -5,6 +5,7 @@
 using System.Text;
 using Microsoft.AspNetCore.Html;
 using Microsoft.DotNet.Interactive.Formatting;
+using Microsoft.DotNet.Interactive.Formatting.TabularData;
 using Microsoft.DotNet.Interactive.Http;
 
 namespace Microsoft.DotNet.Interactive.ExtensionLab
@@ -41,7 +42,7 @@ protected override IHtmlContent ToHtml()
         {
             var requireUri = new Uri("https://cdnjs.cloudflare.com/ajax/libs/require.js/2.3.6/require.min.js");
             var divId = Id;
-            var data = Data.ToJson();
+            var data = Data.ToJsonString();
             var code = new StringBuilder();
             var functionName = $"renderNteractDataExplorer_{divId}";
 

src/Microsoft.DotNet.Interactive.ExtensionLab/SQLiteKernel.cs

@@ -9,6 +9,7 @@
 using System.Threading.Tasks;
 using Microsoft.DotNet.Interactive.Commands;
 using Microsoft.DotNet.Interactive.Formatting;
+using Microsoft.DotNet.Interactive.Formatting.TabularData;
 using Enumerable = System.Linq.Enumerable;
 
 namespace Microsoft.DotNet.Interactive.ExtensionLab

src/Microsoft.DotNet.Interactive.ExtensionLab/SandDanceDataExplorer.cs

@@ -4,7 +4,7 @@
 using System;
 using System.Text;
 using Microsoft.AspNetCore.Html;
-using Microsoft.DotNet.Interactive.Formatting;
+using Microsoft.DotNet.Interactive.Formatting.TabularData;
 using Microsoft.DotNet.Interactive.Http;
 
 namespace Microsoft.DotNet.Interactive.ExtensionLab
@@ -41,7 +41,7 @@ protected override IHtmlContent ToHtml()
         {
             var requireUri = new Uri("https://cdnjs.cloudflare.com/ajax/libs/require.js/2.3.6/require.min.js");
             var divId = Id;
-            var data = Data.ToJson();
+            var data = Data.ToJsonString();
             var code = new StringBuilder();
             var functionName = $"renderSandDanceExplorer_{divId}";
 

src/Microsoft.DotNet.Interactive.ExtensionLab/System.Collections.Generic/EnumerableExtensions.cs

@@ -4,6 +4,7 @@
 using System.Linq;
 using Microsoft.DotNet.Interactive.ExtensionLab;
 using Microsoft.DotNet.Interactive.Formatting;
+using Microsoft.DotNet.Interactive.Formatting.TabularData;
 
 namespace System.Collections.Generic
 {

src/Microsoft.DotNet.Interactive.ExtensionLab/TabularDataResourceExtensions.cs

@@ -3,6 +3,7 @@
 
 
 using Microsoft.DotNet.Interactive.ExtensionLab;
+using Microsoft.DotNet.Interactive.Formatting.TabularData;
 
 namespace Microsoft.DotNet.Interactive.Formatting
 {

src/Microsoft.DotNet.Interactive.Formatting.Tests/FormatterTestBase.cs

@@ -8,7 +8,7 @@ namespace Microsoft.DotNet.Interactive.Formatting.Tests
 {
     public abstract class FormatterTestBase : IDisposable
     {
-        private static readonly object _lock = new object();
+        private static readonly object _lock = new();
 
         protected FormatterTestBase()
         {