Integrate SqlParser into the onchange diagnostics to provide error messages.

src/ServiceHost/LanguageSupport/LanguageService.cs

@@ -5,6 +5,8 @@
 
 using Microsoft.SqlTools.EditorServices;
 using Microsoft.SqlTools.EditorServices.Session;
+using Microsoft.SqlServer.Management.SqlParser.Parser;
+using System.Collections.Generic;
 
 namespace Microsoft.SqlTools.LanguageSupport
 {
@@ -13,6 +15,11 @@ namespace Microsoft.SqlTools.LanguageSupport
     /// </summary>
     public class LanguageService
     {
+        /// <summary>
+        /// The cached parse result from previous incremental parse
+        /// </summary>
+        private ParseResult prevParseResult;
+
         /// <summary>
         /// Gets or sets the current SQL Tools context
         /// </summary>
@@ -34,24 +41,38 @@ namespace Microsoft.SqlTools.LanguageSupport
         /// <param name="scriptFile"></param>
         public ScriptFileMarker[] GetSemanticMarkers(ScriptFile scriptFile)
         {
-            // the commented out snippet is an example of how to create a error marker
-            // semanticMarkers = new ScriptFileMarker[1];
-            // semanticMarkers[0] = new ScriptFileMarker()
-            // {
-            //     Message = "Error message",
-            //     Level = ScriptFileMarkerLevel.Error,
-            //     ScriptRegion = new ScriptRegion()
-            //     {
-            //         File = scriptFile.FilePath,
-            //         StartLineNumber = 2,
-            //         StartColumnNumber = 2,  
-            //         StartOffset = 0,
-            //         EndLineNumber = 4,
-            //         EndColumnNumber = 10,
-            //         EndOffset = 0
-            //     }
-            // };
-            return new ScriptFileMarker[0];
+            // parse current SQL file contents to retrieve a list of errors
+            ParseOptions parseOptions = new ParseOptions();
+            ParseResult parseResult = Parser.IncrementalParse(
+                scriptFile.Contents,
+                prevParseResult,
+                parseOptions);
+
+            // save previous result for next incremental parse
+            this.prevParseResult = parseResult;
+
+            // build a list of SQL script file markers from the errors
+            List<ScriptFileMarker> markers = new List<ScriptFileMarker>();
+            foreach (var error in parseResult.Errors)
+            {
+                markers.Add(new ScriptFileMarker()
+                {
+                    Message = error.Message,
+                    Level = ScriptFileMarkerLevel.Error,
+                    ScriptRegion = new ScriptRegion()
+                    {
+                        File = scriptFile.FilePath,
+                        StartLineNumber = error.Start.LineNumber,
+                        StartColumnNumber = error.Start.ColumnNumber,  
+                        StartOffset = 0,
+                        EndLineNumber = error.End.LineNumber,
+                        EndColumnNumber = error.End.ColumnNumber,
+                        EndOffset = 0
+                    }
+                });
+            }
+            
+            return markers.ToArray();
         }
     }
 }

src/ServiceHost/Server/LanguageServer.cs

@@ -122,7 +122,7 @@ namespace Microsoft.SqlTools.EditorServices.Protocol.Server
         /// <param name="textChangeParams"></param>
         /// <param name="eventContext"></param>
         /// <returns></returns>
-        protected Task HandleDidChangeTextDocumentNotification(
+        protected async Task HandleDidChangeTextDocumentNotification(
             DidChangeTextDocumentParams textChangeParams,
             EventContext eventContext)
         {
@@ -133,7 +133,7 @@ namespace Microsoft.SqlTools.EditorServices.Protocol.Server
             // A text change notification can batch multiple change requests
             foreach (var textChange in textChangeParams.ContentChanges)
             {
-                string fileUri = textChangeParams.TextDocument.Uri;
+                string fileUri = textChangeParams.Uri ?? textChangeParams.TextDocument.Uri;
                 msg.AppendLine();
                 msg.Append("  File: ");
                 msg.Append(fileUri);
@@ -150,12 +150,12 @@ namespace Microsoft.SqlTools.EditorServices.Protocol.Server
 
             Logger.Write(LogLevel.Verbose, msg.ToString());
 
-            this.RunScriptDiagnostics(
+            await this.RunScriptDiagnostics(
                 changedFiles.ToArray(),
                 editorSession,
                 eventContext);
 
-            return Task.FromResult(true);
+            await Task.FromResult(true);
         }
 
         protected Task HandleDidOpenTextDocumentNotification(

src/ServiceHost/project.json

@@ -5,7 +5,8 @@
     "emitEntryPoint": true
   },
   "dependencies": {
-    "Newtonsoft.Json": "9.0.1"
+    "Newtonsoft.Json": "9.0.1",
+    "Microsoft.SqlServer.SqlParser": "140.1.3"
   },
   "frameworks": {
     "netcoreapp1.0": {