added rudimentary syntax checking to make life easier for users

Author: daren-thomas

PythonConsoleControl/PythonConsole.cs

@@ -381,7 +381,17 @@ void ExecuteStatements()
                 try
                 {
                     executing = true;
-                    GetCommandDispatcher()(() => scriptSource.Execute(commandLine.ScriptScope));
+                    var errors = new ErrorReporter();
+                    var command = scriptSource.Compile(errors);
+                    if (command == null)
+                    {
+                        // compilation failed
+                        error = "Syntax Error: " + string.Join("\nSyntax Error: ", errors.Errors) + "\n";
+                    }
+                    else
+                    {
+                        GetCommandDispatcher()(() => scriptSource.Execute(commandLine.ScriptScope));
+                    }                    
                 }
                 catch (ThreadAbortException tae)
                 {
@@ -715,4 +725,19 @@ void ReplaceCurrentLineTextAfterPrompt(string text)
             textEditor.Column = promptLength + text.Length + 1;
         }
     }
+
+    public class ErrorReporter : ErrorListener
+    {
+        public List<String> Errors = new List<string>();
+
+        public override void ErrorReported(ScriptSource source, string message, SourceSpan span, int errorCode, Severity severity)
+        {
+            Errors.Add(string.Format("{0} (line {1})", message, span.Start.Line));
+        }
+
+        public int Count
+        {
+            get { return Errors.Count; }
+        }
+    }
 }

RpsRuntime/ScriptExecutor.cs

@@ -80,6 +80,16 @@ public int ExecuteScript(string source, string sourcePath)
                 engine.Runtime.IO.SetInput(outputStream, Encoding.UTF8);
 
                 var script = engine.CreateScriptSourceFromString(source, SourceCodeKind.Statements);
+                var errors = new ErrorReporter();
+                var command = script.Compile(errors);
+                if (command == null)
+                {
+                    // compilation failed
+                    _message = string.Join("\n", errors.Errors);
+                    return (int)Result.Failed;
+                }
+
+
                 try
                 {
                     script.Execute(scope);
@@ -195,4 +205,20 @@ private void AddSearchPaths(ScriptEngine engine)
             engine.SetSearchPaths(searchPaths);
         }
     }
+
+
+    public class ErrorReporter : ErrorListener
+    {
+        public List<String> Errors = new List<string>();
+
+        public override void ErrorReported(ScriptSource source, string message, SourceSpan span, int errorCode, Severity severity)
+        {
+            Errors.Add(string.Format("{0} (line {1})", message, span.Start.Line));
+        }
+
+        public int Count
+        {
+            get { return Errors.Count; }
+        }
+    }
 }