Added ErrorExpression to provide feedback for malformed Expressions

Author: Vogel612

RetailCoder.VBE/UI/RegexAssistant/RegexAssistantViewModel.cs

@@ -1,7 +1,6 @@
 using Rubberduck.RegexAssistant;
 using System.Collections.Generic;
 using System.Linq;
-using System.Threading.Tasks;
 using System.Windows.Controls;
 
 namespace Rubberduck.UI.RegexAssistant
@@ -99,8 +98,6 @@ public string DescriptionResults
 
         private static TreeViewItem AsTreeViewItem(IRegularExpression expression)
         {
-            var t = expression.GetType();
-
             var result = new TreeViewItem();
             result.Header = "Some unknown IRegularExpression subtype was in the view";
             foreach (var subtree in expression.Subexpressions.Select(exp => AsTreeViewItem((dynamic)exp)))
@@ -110,6 +107,13 @@ private static TreeViewItem AsTreeViewItem(IRegularExpression expression)
             return result;
         }
 
+        private static TreeViewItem AsTreeViewItem(ErrorExpression expression)
+        {
+            var result = new TreeViewItem();
+            result.Header = expression.Description;
+            return result;
+        }
+
         private static TreeViewItem AsTreeViewItem(ConcatenatedExpression expression)
         {
             var result = new TreeViewItem();

Rubberduck.RegexAssistant/Atom.cs

@@ -133,7 +133,8 @@ public string Description
         {
             get
             {
-                return string.Format(AssistantResources.AtomDescription_Group, _specifier) + "\r\n" + _subexpression.Description;
+                return string.Format(AssistantResources.AtomDescription_Group, _specifier);
+                //+"\r\n" + _subexpression.Description
             }
         }
 

Rubberduck.RegexAssistant/IRegularExpression.cs

@@ -139,6 +139,40 @@ public override int GetHashCode()
 
     }
 
+    public class ErrorExpression : IRegularExpression
+    {
+        private readonly string _errorToken;
+
+        public ErrorExpression(string errorToken)
+        {
+            _errorToken = errorToken;
+        }
+
+        public string Description
+        {
+            get
+            {
+                return string.Format(AssistantResources.ExpressionDescription_ErrorExpression, _errorToken);
+            }
+        }
+
+        public Quantifier Quantifier
+        {
+            get
+            {
+                return new Quantifier(string.Empty);
+            }
+        }
+
+        public IList<IRegularExpression> Subexpressions
+        {
+            get
+            {
+                return new List<IRegularExpression>();
+            }
+        }
+    }
+
     internal static class RegularExpression
     {
 
@@ -208,6 +242,11 @@ private static IRegularExpression ParseIntoConcatenatedExpression(ref string spe
                 {
                     subexpressions.Add(expression);
                 }
+                else if (currentSpecifier.Length == oldSpecifierLength)
+                {
+                    subexpressions.Add(new ErrorExpression(currentSpecifier.Substring(0, 1)));
+                    currentSpecifier = currentSpecifier.Substring(1);
+                }
             }
             specifier = ""; // we've exhausted the specifier, tell Parse about it to prevent infinite looping
             return new ConcatenatedExpression(subexpressions);

Rubberduck.RegexAssistant/i18n/AssistantResources.Designer.cs

@@ -192,6 +192,9 @@
   <data name="ExpressionDescription_ConcatenatedExpression" xml:space="preserve">
     <value>Matches the exact sequence given as follows:</value>
   </data>
+  <data name="ExpressionDescription_ErrorExpression" xml:space="preserve">
+    <value>Could not parse {0} as literal. Check your input, please</value>
+  </data>
   <data name="PatternDescription_AnchorEnd" xml:space="preserve">
     <value>$ ensures all characters of the string are consumed</value>
   </data>