Added error messages for a negative channel argument

Author: wiredwiz

Grun/Program.cs

@@ -124,6 +124,11 @@ private static void Main(string[] args)
                                showParseTree = true;
                             }
 
+                            if (o.Channel < 0)
+                            {
+                               Console.WriteLine(Resources.NegativeChannelErrMsg);
+                               return;
+                            }
                             channel = o.Channel;
 
                             if (!string.IsNullOrEmpty(o.SvgFileName))

Grun/Properties/Resources.Designer.cs

@@ -141,4 +141,7 @@
   <data name="FileNotFoundErrorMessage" xml:space="preserve">
     <value>File "{0}" could not be found.</value>
   </data>
+  <data name="NegativeChannelErrMsg" xml:space="preserve">
+    <value>Channel must not be a negative number</value>
+  </data>
 </root>

Grun/Properties/Resources.resx

@@ -82,6 +82,8 @@ private static void Main(string[] args)
                            visualAnalyzer.LoadSourceFile(o.FileName, encodingToUse);
                         }
 
+                        if (o.Channel < 0)
+                           throw new ArgumentException("Channel must not be negative");
                         visualAnalyzer.TokenChannel = o.Channel;
 
                         if (o.Diagnostics) visualAnalyzer.ParseWithDiagnostics = true;