fix some bugs in the editor; catch parse failures in the path host; add a bunch of path lessons

Author: gregsdennis

LearnJsonEverything.LessonEditor/Controls/Editor.xaml.cs

@@ -96,12 +96,19 @@ private void ValidateSolution(object sender, RoutedEventArgs e)
 	{
 		if (SelectedLesson is null) return;
 
-		SelectedLesson.Save();
+		try
+		{
+			SelectedLesson.Save();
 
-		SelectedLesson.Lesson.UserCode = SelectedLesson.Solution;
-		var output = LessonHost.Run(SelectedLesson.Lesson);
-		ValidationOutput = string.Join(Environment.NewLine, output);
-		CanSave = output.All(x => x.StartsWith(Iconography.SuccessIcon));
+			SelectedLesson.Lesson.UserCode = SelectedLesson.Solution;
+			var output = LessonHost.Run(SelectedLesson.Lesson);
+			ValidationOutput = string.Join(Environment.NewLine, output);
+			CanSave = output.All(x => x.StartsWith(Iconography.SuccessIcon));
+		}
+		catch (Exception exception)
+		{
+			ValidationOutput = exception.Message + Environment.NewLine + exception.StackTrace;
+		}
 	}
 
 	private void SaveChanges(object sender, RoutedEventArgs e)

LearnJsonEverything/Services/Hosts/PathHost.cs

@@ -17,7 +17,16 @@ public string[] Run(LessonData lesson)
 		foreach (var test in lesson.Tests)
 		{
 			var expectedResult = test!["result"];
-			var result = runner.Run(test.AsObject());
+			PathResult? result = null;
+			try
+			{
+				result = runner.Run(test.AsObject());
+			}
+			catch
+			{
+				// ignored
+			}
+
 			var localResult = expectedResult.IsEquivalentTo(result?.Matches?.Select(x => x.Value).ToJsonArray());
 			correct &= localResult;
 			results.Add($"{(localResult ? Iconography.SuccessIcon : Iconography.ErrorIcon)} {test.Print()}");