From 2c2ef65f89dff72609040da2910a8884ddf86905 Mon Sep 17 00:00:00 2001
From: Daniel Grunwald <daniel@danielgrunwald.de>
Date: Sun, 22 Mar 2009 01:05:59 +0000
Subject: [PATCH] Improved GetNextCaretPosition - placed word borders at line
 starts and ends. Implemented GetWordBeforeCaret().

git-svn-id: svn://svn.sharpdevelop.net/sharpdevelop/trunk@3901 1ccf3a8d-04fe-1044-b7c0-cef0b8235c61
---
 .../Src/AvalonEditDocumentAdapter.cs          |   5 +
 .../AvalonEdit.AddIn/Src/CodeEditor.cs        |   5 +-
 .../Src/SharpDevelopCompletionWindow.cs       |   5 +-
 .../ICSharpCode.AvalonEdit.Tests.csproj       |   1 +
 .../Utils/CaretNavigationTests.cs             |  91 ++++++++++++++
 .../CodeCompletion/CompletionWindow.cs        |  20 +--
 .../Document/ITextSource.cs                   |  55 +++++++++
 .../ICSharpCode.AvalonEdit/Gui/Caret.cs       |   4 +-
 .../Gui/NewLineElementGenerator.cs            |   6 +-
 .../ICSharpCode.AvalonEdit/Gui/VisualLine.cs  |  34 ++++++
 .../Gui/VisualLineElement.cs                  |  14 ++-
 .../Gui/VisualLineText.cs                     |  44 ++-----
 .../Gui/WhitespaceElementGenerator.cs         |  10 +-
 .../Utils/TextUtilities.cs                    | 114 ++++++++++++++++++
 .../Project/ICSharpCode.SharpDevelop.csproj   |  15 ++-
 .../RefactoringService/TextEditorDocument.cs  |   5 +
 .../Src/TextEditor/DocumentUtilitites.cs      |  86 +++++++++++++
 .../Gui/Editor/CodeCompletionBinding.cs       |   5 +-
 .../Project/Src/TextEditor/ITextEditor.cs     |   1 -
 .../Project/Src/Refactoring/IDocument.cs      |   1 +
 20 files changed, 458 insertions(+), 63 deletions(-)
 create mode 100644 src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit.Tests/Utils/CaretNavigationTests.cs
 create mode 100644 src/Main/Base/Project/Src/TextEditor/DocumentUtilitites.cs

diff --git a/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/AvalonEditDocumentAdapter.cs b/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/AvalonEditDocumentAdapter.cs
index 990120223e..8540b37e7c 100644
--- a/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/AvalonEditDocumentAdapter.cs
+++ b/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/AvalonEditDocumentAdapter.cs
@@ -71,6 +71,11 @@ namespace ICSharpCode.AvalonEdit.AddIn
 			set { document.Text = value; }
 		}
 		
+		public event EventHandler TextChanged {
+			add { document.TextChanged += value; }
+			remove { document.TextChanged -= value; }
+		}
+		
 		public IDocumentLine GetLine(int lineNumber)
 		{
 			return new LineAdapter(document.GetLineByNumber(lineNumber));
diff --git a/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/CodeEditor.cs b/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/CodeEditor.cs
index 93aed1c6e9..25c9d281a7 100644
--- a/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/CodeEditor.cs
+++ b/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/CodeEditor.cs
@@ -52,9 +52,8 @@ namespace ICSharpCode.AvalonEdit.AddIn
 					if (result == CodeCompletionKeyPressResult.Completed) {
 						if (lastCompletionWindow != null && lastCompletionWindow != oldCompletionWindow) {
 							// a new CompletionWindow was shown, but does not eat the input
-							// increment the offsets so that they are correct after the text insertion
-							lastCompletionWindow.StartOffset++;
-							lastCompletionWindow.EndOffset++;
+							// tell it to expect the text insertion
+							lastCompletionWindow.ExpectInsertionBeforeStart = true;
 						}
 						return;
 					} else if (result == CodeCompletionKeyPressResult.EatKey) {
diff --git a/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/SharpDevelopCompletionWindow.cs b/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/SharpDevelopCompletionWindow.cs
index 8d104919f8..9edf23dac9 100644
--- a/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/SharpDevelopCompletionWindow.cs
+++ b/src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/SharpDevelopCompletionWindow.cs
@@ -38,10 +38,7 @@ namespace ICSharpCode.AvalonEdit.AddIn
 				foreach (char c in e.Text) {
 					switch (itemList.ProcessInput(c)) {
 						case CompletionItemListKeyResult.BeforeStartKey:
-							if (StartOffset == EndOffset) {
-								StartOffset++;
-								EndOffset++;
-							}
+							this.ExpectInsertionBeforeStart = true;
 							break;
 						case CompletionItemListKeyResult.NormalKey:
 							break;
diff --git a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit.Tests/ICSharpCode.AvalonEdit.Tests.csproj b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit.Tests/ICSharpCode.AvalonEdit.Tests.csproj
index 0c73263bde..54fd01f4ba 100644
--- a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit.Tests/ICSharpCode.AvalonEdit.Tests.csproj
+++ b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit.Tests/ICSharpCode.AvalonEdit.Tests.csproj
@@ -72,6 +72,7 @@
     <Compile Include="Document\HeightTests.cs" />
     <Compile Include="Document\RandomizedLineManagerTest.cs" />
     <Compile Include="Document\LineManagerTests.cs" />
+    <Compile Include="Utils\CaretNavigationTests.cs" />
     <Compile Include="Utils\CompressingTreeListTests.cs" />
     <Compile Include="Utils\ExtensionMethodsTests.cs" />
     <Compile Include="WeakReferenceTests.cs" />
diff --git a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit.Tests/Utils/CaretNavigationTests.cs b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit.Tests/Utils/CaretNavigationTests.cs
new file mode 100644
index 0000000000..f86f651032
--- /dev/null
+++ b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit.Tests/Utils/CaretNavigationTests.cs
@@ -0,0 +1,91 @@
+// <file>
+//     <copyright see="prj:///doc/copyright.txt"/>
+//     <license see="prj:///doc/license.txt"/>
+//     <author name="Daniel Grunwald"/>
+//     <version>$Revision$</version>
+// </file>
+
+using ICSharpCode.AvalonEdit.Gui;
+using System;
+using ICSharpCode.AvalonEdit.Document;
+using ICSharpCode.AvalonEdit.Utils;
+using NUnit.Framework;
+
+namespace ICSharpCode.AvalonEdit.Tests.Utils
+{
+	[TestFixture]
+	public class CaretNavigationTests
+	{
+		int GetNextCaretStop(string text, int offset, CaretPositioningMode mode)
+		{
+			return TextUtilities.GetNextCaretPosition(new StringTextSource(text), offset, false, mode);
+		}
+		
+		int GetPrevCaretStop(string text, int offset, CaretPositioningMode mode)
+		{
+			return TextUtilities.GetNextCaretPosition(new StringTextSource(text), offset, true, mode);
+		}
+		
+		[Test]
+		public void CaretStopInEmptyString()
+		{
+			Assert.AreEqual(0, GetNextCaretStop("", -1, CaretPositioningMode.Normal));
+			Assert.AreEqual(-1, GetNextCaretStop("", 0, CaretPositioningMode.Normal));
+			Assert.AreEqual(-1, GetPrevCaretStop("", 0, CaretPositioningMode.Normal));
+			Assert.AreEqual(0, GetPrevCaretStop("", 1, CaretPositioningMode.Normal));
+			
+			Assert.AreEqual(-1, GetNextCaretStop("", -1, CaretPositioningMode.WordStart));
+			Assert.AreEqual(-1, GetNextCaretStop("", -1, CaretPositioningMode.WordBorder));
+			Assert.AreEqual(-1, GetPrevCaretStop("", 1, CaretPositioningMode.WordStart));
+			Assert.AreEqual(-1, GetPrevCaretStop("", 1, CaretPositioningMode.WordBorder));
+		}
+		
+		[Test]
+		public void StartOfDocumentWithWordStart()
+		{
+			Assert.AreEqual(0, GetNextCaretStop("word", -1, CaretPositioningMode.Normal));
+			Assert.AreEqual(0, GetNextCaretStop("word", -1, CaretPositioningMode.WordStart));
+			Assert.AreEqual(0, GetNextCaretStop("word", -1, CaretPositioningMode.WordBorder));
+			
+			Assert.AreEqual(0, GetPrevCaretStop("word", 1, CaretPositioningMode.Normal));
+			Assert.AreEqual(0, GetPrevCaretStop("word", 1, CaretPositioningMode.WordStart));
+			Assert.AreEqual(0, GetPrevCaretStop("word", 1, CaretPositioningMode.WordBorder));
+		}
+		
+		[Test]
+		public void StartOfDocumentNoWordStart()
+		{
+			Assert.AreEqual(0, GetNextCaretStop(" word", -1, CaretPositioningMode.Normal));
+			Assert.AreEqual(1, GetNextCaretStop(" word", -1, CaretPositioningMode.WordStart));
+			Assert.AreEqual(1, GetNextCaretStop(" word", -1, CaretPositioningMode.WordBorder));
+			
+			Assert.AreEqual(0, GetPrevCaretStop(" word", 1, CaretPositioningMode.Normal));
+			Assert.AreEqual(-1, GetPrevCaretStop(" word", 1, CaretPositioningMode.WordStart));
+			Assert.AreEqual(-1, GetPrevCaretStop(" word", 1, CaretPositioningMode.WordBorder));
+		}
+		
+		[Test]
+		public void EndOfDocumentWordBorder()
+		{
+			Assert.AreEqual(4, GetNextCaretStop("word", 3, CaretPositioningMode.Normal));
+			Assert.AreEqual(-1, GetNextCaretStop("word", 3, CaretPositioningMode.WordStart));
+			Assert.AreEqual(4, GetNextCaretStop("word", 3, CaretPositioningMode.WordBorder));
+			
+			Assert.AreEqual(4, GetPrevCaretStop("word", 5, CaretPositioningMode.Normal));
+			Assert.AreEqual(0, GetPrevCaretStop("word", 5, CaretPositioningMode.WordStart));
+			Assert.AreEqual(4, GetPrevCaretStop("word", 5, CaretPositioningMode.WordBorder));
+		}
+		
+		[Test]
+		public void EndOfDocumentNoWordBorder()
+		{
+			Assert.AreEqual(4, GetNextCaretStop("txt ", 3, CaretPositioningMode.Normal));
+			Assert.AreEqual(-1, GetNextCaretStop("txt ", 3, CaretPositioningMode.WordStart));
+			Assert.AreEqual(-1, GetNextCaretStop("txt ", 3, CaretPositioningMode.WordBorder));
+			
+			Assert.AreEqual(4, GetPrevCaretStop("txt ", 5, CaretPositioningMode.Normal));
+			Assert.AreEqual(0, GetPrevCaretStop("txt ", 5, CaretPositioningMode.WordStart));
+			Assert.AreEqual(3, GetPrevCaretStop("txt ", 5, CaretPositioningMode.WordBorder));
+		}
+	}
+}
diff --git a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/CodeCompletion/CompletionWindow.cs b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/CodeCompletion/CompletionWindow.cs
index 5fd5b2bfc9..3621775b38 100644
--- a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/CodeCompletion/CompletionWindow.cs
+++ b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/CodeCompletion/CompletionWindow.cs
@@ -163,19 +163,21 @@ namespace ICSharpCode.AvalonEdit.CodeCompletion
 			return completionList.ScrollViewer ?? completionList.ListBox ?? (UIElement)completionList;
 		}
 		
+		/// <summary>
+		/// Gets/sets whether the completion window should expect text insertion at the start offset,
+		/// which not go into the completion region, but before it.
+		/// </summary>
+		public bool ExpectInsertionBeforeStart { get; set; }
+		
 		void textArea_Document_Changing(object sender, DocumentChangeEventArgs e)
 		{
-			// => startOffset test required so that this startOffset/endOffset are not incremented again
-			//    for BeforeStartKey characters
-			if (e.Offset >= startOffset && e.Offset <= endOffset) {
-				endOffset += e.InsertionLength - e.RemovalLength;
-			} else if (e.Offset == startOffset - 1 && e.InsertionLength == 1 && e.RemovalLength == 0) {
-				// allow one-character insertion in front of StartOffset.
-				// this is necessary because for dot-completion, the CompletionWindow is shown before
-				// the dot is actually inserted.
+			if (e.Offset == startOffset && e.RemovalLength == 0 && ExpectInsertionBeforeStart) {
+				startOffset = e.GetNewOffset(startOffset, AnchorMovementType.AfterInsertion);
+				this.ExpectInsertionBeforeStart = false;
 			} else {
-				Close();
+				startOffset = e.GetNewOffset(startOffset, AnchorMovementType.BeforeInsertion);
 			}
+			endOffset = e.GetNewOffset(endOffset, AnchorMovementType.AfterInsertion);
 		}
 		
 		/// <summary>
diff --git a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Document/ITextSource.cs b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Document/ITextSource.cs
index f348a7a6a9..2c1f8cf6a8 100644
--- a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Document/ITextSource.cs
+++ b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Document/ITextSource.cs
@@ -54,6 +54,61 @@ namespace ICSharpCode.AvalonEdit.Document
 		string GetText(int offset, int length);
 	}
 	
+	/// <summary>
+	/// Implements the ITextSource interface by wrapping another TextSource
+	/// and viewing only a part of the text.
+	/// </summary>
+	public sealed class TextSourceView : ITextSource
+	{
+		readonly ITextSource baseTextSource;
+		readonly ISegment viewedSegment;
+		
+		/// <summary>
+		/// Creates a new TextSourceView object.
+		/// </summary>
+		/// <param name="baseTextSource">The base text source.</param>
+		/// <param name="viewedSegment">A text segment from the base text source</param>
+		public TextSourceView(ITextSource baseTextSource, ISegment viewedSegment)
+		{
+			if (baseTextSource == null)
+				throw new ArgumentNullException("baseTextSource");
+			if (viewedSegment == null)
+				throw new ArgumentNullException("viewedSegment");
+			this.baseTextSource = baseTextSource;
+			this.viewedSegment = viewedSegment;
+		}
+		
+		/// <inheritdoc/>
+		public event EventHandler TextChanged {
+			add { baseTextSource.TextChanged += value; }
+			remove { baseTextSource.TextChanged -= value; }
+		}
+		
+		/// <inheritdoc/>
+		public string Text {
+			get {
+				return baseTextSource.GetText(viewedSegment.Offset, viewedSegment.Length); 
+			}
+		}
+		
+		/// <inheritdoc/>
+		public int TextLength {
+			get { return viewedSegment.Length; }
+		}
+		
+		/// <inheritdoc/>
+		public char GetCharAt(int offset)
+		{
+			return baseTextSource.GetCharAt(viewedSegment.Offset + offset);
+		}
+		
+		/// <inheritdoc/>
+		public string GetText(int offset, int length)
+		{
+			return baseTextSource.GetText(viewedSegment.Offset + offset, length);
+		}
+	}
+	
 	/// <summary>
 	/// Implements the ITextSource interface using a string.
 	/// </summary>
diff --git a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Gui/Caret.cs b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Gui/Caret.cs
index 8ca3fe0cc1..7c48089200 100644
--- a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Gui/Caret.cs
+++ b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Gui/Caret.cs
@@ -242,7 +242,9 @@ namespace ICSharpCode.AvalonEdit.Gui
 		
 		Rect CalcCaretRectangle(VisualLine visualLine)
 		{
-			RevalidateVisualColumn(visualLine);
+			if (!visualColumnValid) {
+				RevalidateVisualColumn(visualLine);
+			}
 			
 			TextLine textLine = visualLine.GetTextLine(position.VisualColumn);
 			double xPos = textLine.GetDistanceFromCharacterHit(new CharacterHit(position.VisualColumn, 0));
diff --git a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Gui/NewLineElementGenerator.cs b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Gui/NewLineElementGenerator.cs
index de34962a90..4b80e271b1 100644
--- a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Gui/NewLineElementGenerator.cs
+++ b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Gui/NewLineElementGenerator.cs
@@ -57,7 +57,7 @@ namespace ICSharpCode.AvalonEdit.Gui
 			return new NewLineTextElement(text);
 		}
 		
-		class NewLineTextElement : FormattedTextElement
+		sealed class NewLineTextElement : FormattedTextElement
 		{
 			public NewLineTextElement(FormattedText text) : base(text, 0)
 			{
@@ -76,6 +76,10 @@ namespace ICSharpCode.AvalonEdit.Gui
 					return -1;
 				}
 			}
+			
+			public override bool HandlesLineBorders {
+				get { return true; }
+			}
 		}
 	}
 }
diff --git a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Gui/VisualLine.cs b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Gui/VisualLine.cs
index 7b5e706583..6f2cecd077 100644
--- a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Gui/VisualLine.cs
+++ b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Gui/VisualLine.cs
@@ -317,12 +317,31 @@ namespace ICSharpCode.AvalonEdit.Gui
 		/// </summary>
 		public int GetNextCaretPosition(int visualColumn, bool backwards, CaretPositioningMode mode)
 		{
+			if (elements.Count == 0) {
+				// special handling for empty visual lines:
+				// even though we don't have any elements,
+				// there's a single caret stop at visualColumn 0
+				if (visualColumn < 0 && !backwards)
+					return 0;
+				else if (visualColumn > 0 && backwards)
+					return 0;
+				else
+					return -1;
+			}
+			
 			int i;
 			if (backwards) {
+				// Search Backwards:
+				// If the last element doesn't handle line borders, return the line end as caret stop
+				if (visualColumn > this.VisualLength && !elements[elements.Count-1].HandlesLineBorders) {
+					return this.VisualLength;
+				}
+				// skip elements that start after or at visualColumn
 				for (i = elements.Count - 1; i >= 0; i--) {
 					if (elements[i].VisualColumn < visualColumn)
 						break;
 				}
+				// search last element that has a caret stop
 				for (; i >= 0; i--) {
 					int pos = elements[i].GetNextCaretPosition(
 						Math.Min(visualColumn, elements[i].VisualColumn + elements[i].VisualLength + 1),
@@ -330,11 +349,21 @@ namespace ICSharpCode.AvalonEdit.Gui
 					if (pos >= 0)
 						return pos;
 				}
+				// if we've found nothing, and the first element doesn't handle line borders,
+				// return the line start as caret stop
+				if (visualColumn > 0 && !elements[0].HandlesLineBorders)
+					return 0;
 			} else {
+				// Search Forwards:
+				// If the first element doesn't handle line borders, return the line start as caret stop
+				if (visualColumn < 0 && !elements[0].HandlesLineBorders)
+					return 0;
+				// skip elements that end before or at visualColumn
 				for (i = 0; i < elements.Count; i++) {
 					if (elements[i].VisualColumn + elements[i].VisualLength > visualColumn)
 						break;
 				}
+				// search first element that has a caret stop
 				for (; i < elements.Count; i++) {
 					int pos = elements[i].GetNextCaretPosition(
 						Math.Max(visualColumn, elements[i].VisualColumn - 1),
@@ -342,7 +371,12 @@ namespace ICSharpCode.AvalonEdit.Gui
 					if (pos >= 0)
 						return pos;
 				}
+				// if we've found nothing, and the last element doesn't handle line borders,
+				// return the line end as caret stop
+				if (visualColumn < this.VisualLength && !elements[elements.Count-1].HandlesLineBorders)
+					return this.VisualLength;
 			}
+			// we've found nothing, return -1 and let the caret search continue in the next line
 			return -1;
 		}
 	}
diff --git a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Gui/VisualLineElement.cs b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Gui/VisualLineElement.cs
index 932f677688..fc1d158a1b 100644
--- a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Gui/VisualLineElement.cs
+++ b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Gui/VisualLineElement.cs
@@ -171,7 +171,8 @@ namespace ICSharpCode.AvalonEdit.Gui
 		/// <param name="mode">Whether to stop only at word borders.</param>
 		/// <returns>The visual column of the next caret position, or -1 if there is no next caret position.</returns>
 		/// <remarks>
-		/// In the space between two line elements, usually both of them contain a caret position.
+		/// In the space between two line elements, it is sufficient that one of them contains a caret position;
+		/// though in many cases, both of them contain one.
 		/// </remarks>
 		public virtual int GetNextCaretPosition(int visualColumn, bool backwards, CaretPositioningMode mode)
 		{
@@ -191,6 +192,17 @@ namespace ICSharpCode.AvalonEdit.Gui
 			return -1;
 		}
 		
+		/// <summary>
+		/// Gets whether the <see cref="GetNextCaretPosition"/> implementation handles line borders.
+		/// If this property returns false, the caller of GetNextCaretPosition should handle the line
+		/// borders (i.e. place caret stops at the start and end of the line).
+		/// This property has an effect only for VisualLineElements that are at the start or end of a
+		/// <see cref="VisualLine"/>.
+		/// </summary>
+		public virtual bool HandlesLineBorders {
+			get { return false; }
+		}
+		
 		/// <summary>
 		/// Queries the cursor over the visual line element.
 		/// </summary>
diff --git a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Gui/VisualLineText.cs b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Gui/VisualLineText.cs
index 04d6e5ec7e..6b5408398e 100644
--- a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Gui/VisualLineText.cs
+++ b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Gui/VisualLineText.cs
@@ -5,10 +5,10 @@
 //     <version>$Revision$</version>
 // </file>
 
+using ICSharpCode.AvalonEdit.Utils;
 using System;
 using System.Collections.Generic;
 using System.Windows.Media.TextFormatting;
-
 using ICSharpCode.AvalonEdit.Document;
 
 namespace ICSharpCode.AvalonEdit.Gui
@@ -94,41 +94,15 @@ namespace ICSharpCode.AvalonEdit.Gui
 		/// <inheritdoc/>
 		public override int GetNextCaretPosition(int visualColumn, bool backwards, CaretPositioningMode mode)
 		{
-			int nextPos = backwards ? visualColumn - 1 : visualColumn + 1;
-			if (nextPos >= this.VisualColumn && nextPos <= this.VisualColumn + this.VisualLength) {
-				if (mode == CaretPositioningMode.WordBorder || mode == CaretPositioningMode.WordStart) {
-					TextDocument document = parentVisualLine.FirstDocumentLine.Document;
-					int textOffset = parentVisualLine.FirstDocumentLine.Offset + GetRelativeOffset(nextPos);
-					if (textOffset > 0 && textOffset < document.TextLength) {
-						CharClass charBefore = GetCharClass(document.GetCharAt(textOffset - 1));
-						CharClass charAfter = GetCharClass(document.GetCharAt(textOffset));
-						if (charBefore == charAfter || (charAfter == CharClass.Whitespace && mode == CaretPositioningMode.WordStart))
-							return GetNextCaretPosition(nextPos, backwards, mode);
-					}
-				}
-				return nextPos;
-			}
-			return -1;
-		}
-		
-		enum CharClass
-		{
-			Whitespace,
-			IdentifierPart,
-			LineTerminator,
-			Other
-		}
-		
-		static CharClass GetCharClass(char c)
-		{
-			if (c == '\r' || c == '\n')
-				return CharClass.LineTerminator;	
-			else if (char.IsWhiteSpace(c))
-				return CharClass.Whitespace;
-			else if (char.IsLetterOrDigit(c) || c == '_')
-				return CharClass.IdentifierPart;
+			int textOffset = parentVisualLine.FirstDocumentLine.Offset + this.RelativeTextOffset;
+			TextSourceView view = new TextSourceView(
+				parentVisualLine.FirstDocumentLine.Document,
+				new SimpleSegment(textOffset, this.DocumentLength));
+			int pos = TextUtilities.GetNextCaretPosition(view, visualColumn - this.VisualColumn, backwards, mode);
+			if (pos < 0)
+				return pos;
 			else
-				return CharClass.Other;
+				return this.VisualColumn + pos;
 		}
 	}
 }
diff --git a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Gui/WhitespaceElementGenerator.cs b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Gui/WhitespaceElementGenerator.cs
index 435ca00d5c..17cf46257f 100644
--- a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Gui/WhitespaceElementGenerator.cs
+++ b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Gui/WhitespaceElementGenerator.cs
@@ -93,7 +93,7 @@ namespace ICSharpCode.AvalonEdit.Gui
 			}
 		}
 		
-		class SpaceTextElement : FormattedTextElement
+		sealed class SpaceTextElement : FormattedTextElement
 		{
 			public SpaceTextElement(FormattedText text) : base(text, 1)
 			{
@@ -110,7 +110,7 @@ namespace ICSharpCode.AvalonEdit.Gui
 			}
 		}
 		
-		class TabTextElement : VisualLineElement
+		sealed class TabTextElement : VisualLineElement
 		{
 			internal readonly FormattedText text;
 			
@@ -121,6 +121,8 @@ namespace ICSharpCode.AvalonEdit.Gui
 			
 			public override TextRun CreateTextRun(int startVisualColumn, ITextRunConstructionContext context)
 			{
+				// the TabTextElement consists of two TextRuns:
+				// first a TabGlyphRun, then TextCharacters '\t' to let WPF handle the tab indentation
 				if (startVisualColumn == this.VisualColumn)
 					return new TabGlyphRun(this, this.TextRunProperties);
 				else if (startVisualColumn == this.VisualColumn + 1)
@@ -138,9 +140,9 @@ namespace ICSharpCode.AvalonEdit.Gui
 			}
 		}
 		
-		class TabGlyphRun : TextEmbeddedObject
+		sealed class TabGlyphRun : TextEmbeddedObject
 		{
-			protected readonly TabTextElement element;
+			readonly TabTextElement element;
 			TextRunProperties properties;
 			
 			public TabGlyphRun(TabTextElement element, TextRunProperties properties)
diff --git a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Utils/TextUtilities.cs b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Utils/TextUtilities.cs
index 4bee7a328b..007d66ac6d 100644
--- a/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Utils/TextUtilities.cs
+++ b/src/Libraries/AvalonEdit/ICSharpCode.AvalonEdit/Utils/TextUtilities.cs
@@ -6,6 +6,9 @@
 // </file>
 
 using System;
+using ICSharpCode.AvalonEdit.Document;
+using ICSharpCode.AvalonEdit.Gui;
+using System.ComponentModel;
 
 namespace ICSharpCode.AvalonEdit.Utils
 {
@@ -14,5 +17,116 @@ namespace ICSharpCode.AvalonEdit.Utils
 	/// </summary>
 	public static class TextUtilities
 	{
+		/// <summary>
+		/// Gets whether the character is whitespace, part of an identifier, or line terminator.
+		/// </summary>
+		public static CharacterClass GetCharacterClass(char c)
+		{
+			if (c == '\r' || c == '\n')
+				return CharacterClass.LineTerminator;
+			else if (char.IsWhiteSpace(c))
+				return CharacterClass.Whitespace;
+			else if (char.IsLetterOrDigit(c) || c == '_')
+				return CharacterClass.IdentifierPart;
+			else
+				return CharacterClass.Other;
+		}
+		
+		/// <summary>
+		/// Gets the next caret position.
+		/// </summary>
+		/// <param name="textSource">The text source.</param>
+		/// <param name="offset">The start offset inside the text source.</param>
+		/// <param name="backwards">True to look backwards, false to look forwards.</param>
+		/// <param name="mode">The mode for caret positioning.</param>
+		/// <returns>The offset of the next caret position, or -1 if there is no further caret position
+		/// in the text source.</returns>
+		public static int GetNextCaretPosition(ITextSource textSource, int offset, bool backwards, CaretPositioningMode mode)
+		{
+			if (textSource == null)
+				throw new ArgumentNullException("textSource");
+			if (mode != CaretPositioningMode.Normal
+			    && mode != CaretPositioningMode.WordBorder
+			    && mode != CaretPositioningMode.WordStart)
+			{
+				throw new ArgumentException("Unsupported CaretPositioningMode: " + mode, "mode");
+			}
+			int textLength = textSource.TextLength;
+			if (textLength <= 0) {
+				// empty document? has a normal caret position at 0, though no word borders
+				if (mode == CaretPositioningMode.Normal) {
+					if (offset > 0 && backwards) return 0;
+					if (offset < 0 && !backwards) return 0;
+				}
+				return -1;
+			}
+			while (true) {
+				int nextPos = backwards ? offset - 1 : offset + 1;
+				
+				// return -1 if there is no further caret position in the text source
+				// we also need this to handle offset values outside the valid range
+				if (nextPos < 0 || nextPos > textLength)
+					return -1;
+				
+				// stop at every caret position? we can stop immediately.
+				if (mode == CaretPositioningMode.Normal)
+					return nextPos;
+				// not normal mode? we're looking for word borders...
+				
+				// check if we've run against the textSource borders.
+				// a 'textSource' usually isn't the whole document, but a single VisualLineElement.
+				if (nextPos == 0) {
+					// at the document start, there's only a word border
+					// if the first character is not whitespace
+					if (!char.IsWhiteSpace(textSource.GetCharAt(0)))
+						return nextPos;
+				} else if (nextPos == textLength) {
+					// at the document end, there's never a word start
+					if (mode != CaretPositioningMode.WordStart) {
+						// at the document end, there's only a word border
+						// if the last character is not whitespace
+						if (!char.IsWhiteSpace(textSource.GetCharAt(textLength - 1)))
+							return nextPos;
+					}
+				} else {
+					CharacterClass charBefore = GetCharacterClass(textSource.GetCharAt(nextPos - 1));
+					CharacterClass charAfter = GetCharacterClass(textSource.GetCharAt(nextPos));
+					if (charBefore != charAfter) {
+						// this looks like a possible border
+						
+						// if we're looking for word starts, check that this is a word start (and not a word end)
+						// if we're just checking for word borders, accept unconditionally
+						if (!(mode == CaretPositioningMode.WordStart && (charAfter == CharacterClass.Whitespace || charAfter == CharacterClass.LineTerminator))) {
+							return nextPos;
+						}
+					}
+				}
+				// we'll have to continue searching...
+				offset = nextPos;
+			}
+		}
+	}
+	
+	/// <summary>
+	/// Classifies a character as whitespace, line terminator, part of an identifier, or other.
+	/// </summary>
+	public enum CharacterClass
+	{
+		/// <summary>
+		/// The character is not whitespace, line terminator or part of an identifier.
+		/// </summary>
+		Other,
+		/// <summary>
+		/// The character is whitespace (but not line terminator).
+		/// </summary>
+		Whitespace,
+		/// <summary>
+		/// The character can be part of an identifier (LetterOrDigit or underscore).
+		/// </summary>
+		IdentifierPart,
+		/// <summary>
+		/// The character is line terminator (\r or \n).
+		/// </summary>
+		LineTerminator
 	}
 }
diff --git a/src/Main/Base/Project/ICSharpCode.SharpDevelop.csproj b/src/Main/Base/Project/ICSharpCode.SharpDevelop.csproj
index b01753ae4f..c549c1eab4 100644
--- a/src/Main/Base/Project/ICSharpCode.SharpDevelop.csproj
+++ b/src/Main/Base/Project/ICSharpCode.SharpDevelop.csproj
@@ -512,6 +512,7 @@
     <Compile Include="Src\TextEditor\Commands\TextAreaContextmenuCommands.cs" />
     <Compile Include="Src\TextEditor\Commands\ToolCommands.cs" />
     <Compile Include="Src\TextEditor\Conditions\TextContentCondition.cs" />
+    <Compile Include="Src\TextEditor\DocumentUtilitites.cs" />
     <Compile Include="Src\TextEditor\Gui\Dialogs\GotoDialog.cs">
       <SubType>Form</SubType>
     </Compile>
@@ -750,9 +751,15 @@
     </EmbeddedResource>
   </ItemGroup>
   <ItemGroup>
+    <ProjectReference Include="..\..\..\Libraries\AvalonEdit\ICSharpCode.AvalonEdit\ICSharpCode.AvalonEdit.csproj">
+      <Project>{6C55B776-26D4-4DB3-A6AB-87E783B2F3D1}</Project>
+      <Name>ICSharpCode.AvalonEdit</Name>
+      <Private>True</Private>
+    </ProjectReference>
     <ProjectReference Include="..\..\..\Libraries\ICSharpCode.TextEditor\Project\ICSharpCode.TextEditor.csproj">
       <Project>{2D18BE89-D210-49EB-A9DD-2246FBB3DF6D}</Project>
       <Name>ICSharpCode.TextEditor</Name>
+      <Private>False</Private>
     </ProjectReference>
     <ProjectReference Include="..\..\..\Libraries\NRefactory\Project\NRefactory.csproj">
       <Project>{3A9AE6AA-BC07-4A2F-972C-581E3AE2F195}</Project>
@@ -761,6 +768,7 @@
     <ProjectReference Include="..\..\Core\Project\ICSharpCode.Core.csproj">
       <Project>{35cef10f-2d4c-45f2-9dd1-161e0fec583c}</Project>
       <Name>ICSharpCode.Core</Name>
+      <Private>False</Private>
     </ProjectReference>
     <Folder Include="Src\Gui\Pads\SearchResultPad" />
     <Folder Include="Src\Gui\Pads\SearchResultPad\Nodes" />
@@ -774,25 +782,28 @@
     <ProjectReference Include="..\..\ICSharpCode.Core.Presentation\ICSharpCode.Core.Presentation.csproj">
       <Project>{7E4A7172-7FF5-48D0-B719-7CD959DD1AC9}</Project>
       <Name>ICSharpCode.Core.Presentation</Name>
-      <Private>True</Private>
+      <Private>False</Private>
     </ProjectReference>
     <ProjectReference Include="..\..\ICSharpCode.Core.WinForms\ICSharpCode.Core.WinForms.csproj">
       <Project>{857CA1A3-FC88-4BE0-AB6A-D1EE772AB288}</Project>
       <Name>ICSharpCode.Core.WinForms</Name>
+      <Private>False</Private>
     </ProjectReference>
     <ProjectReference Include="..\..\ICSharpCode.SharpDevelop.BuildWorker\ICSharpCode.SharpDevelop.BuildWorker.csproj">
       <Project>{C3CBC8E3-81D8-4C5B-9941-DCCD12D50B1F}</Project>
       <Name>ICSharpCode.SharpDevelop.BuildWorker</Name>
+      <Private>False</Private>
     </ProjectReference>
     <ProjectReference Include="..\..\ICSharpCode.SharpDevelop.Dom\Project\ICSharpCode.SharpDevelop.Dom.csproj">
       <Project>{924EE450-603D-49C1-A8E5-4AFAA31CE6F3}</Project>
       <Name>ICSharpCode.SharpDevelop.Dom</Name>
+      <Private>False</Private>
     </ProjectReference>
     <Folder Include="Src\Gui\Dialogs\SolutionConfiguration" />
     <ProjectReference Include="..\..\ICSharpCode.SharpDevelop.Widgets\Project\ICSharpCode.SharpDevelop.Widgets.csproj">
       <Project>{8035765F-D51F-4A0C-A746-2FD100E19419}</Project>
       <Name>ICSharpCode.SharpDevelop.Widgets</Name>
-      <Private>True</Private>
+      <Private>False</Private>
     </ProjectReference>
     <Page Include="Src\Gui\App.xaml" />
     <Page Include="Src\Gui\Dialogs\TabbedOptionsDialog.xaml" />
diff --git a/src/Main/Base/Project/Src/Services/RefactoringService/TextEditorDocument.cs b/src/Main/Base/Project/Src/Services/RefactoringService/TextEditorDocument.cs
index d2bd675168..2e4ddda343 100644
--- a/src/Main/Base/Project/Src/Services/RefactoringService/TextEditorDocument.cs
+++ b/src/Main/Base/Project/Src/Services/RefactoringService/TextEditorDocument.cs
@@ -72,6 +72,11 @@ namespace ICSharpCode.SharpDevelop.Refactoring
 			set { doc.TextContent = value; }
 		}
 		
+		public event EventHandler TextChanged {
+			add { doc.TextContentChanged += value; }
+			remove { doc.TextContentChanged -= value; }
+		}
+		
 		public string GetText(int offset, int length)
 		{
 			return doc.GetText(offset, length);
diff --git a/src/Main/Base/Project/Src/TextEditor/DocumentUtilitites.cs b/src/Main/Base/Project/Src/TextEditor/DocumentUtilitites.cs
new file mode 100644
index 0000000000..db11199d79
--- /dev/null
+++ b/src/Main/Base/Project/Src/TextEditor/DocumentUtilitites.cs
@@ -0,0 +1,86 @@
+// <file>
+//     <copyright see="prj:///doc/copyright.txt"/>
+//     <license see="prj:///doc/license.txt"/>
+//     <author name="Daniel Grunwald"/>
+//     <version>$Revision$</version>
+// </file>
+
+using ICSharpCode.AvalonEdit.Gui;
+using System;
+using ICSharpCode.AvalonEdit.Utils;
+using ICSharpCode.SharpDevelop.Dom.Refactoring;
+
+namespace ICSharpCode.SharpDevelop
+{
+	/// <summary>
+	/// Extension methods for ITextEditor and IDocument.
+	/// </summary>
+	public static class DocumentUtilitites
+	{
+		/// <summary>
+		/// Gets the word in front of the caret.
+		/// </summary>
+		public static string GetWordBeforeCaret(this ITextEditor editor)
+		{
+			if (editor == null)
+				throw new ArgumentNullException("editor");
+			int endOffset = editor.Caret.Offset;
+			int startOffset = FindPrevWordStart(editor.Document, endOffset);
+			if (startOffset < 0)
+				return string.Empty;
+			else
+				return editor.Document.GetText(startOffset, endOffset - startOffset);
+		}
+		
+		/// <summary>
+		/// Finds the first word start in the document before offset.
+		/// </summary>
+		/// <returns>The offset of the word start, or -1 if there is no word start before the specified offset.</returns>
+		public static int FindPrevWordStart(IDocument document, int offset)
+		{
+			return TextUtilities.GetNextCaretPosition(GetTextSource(document), offset, true, CaretPositioningMode.WordStart);
+		}
+		
+		#region ITextSource implementation
+		public static ICSharpCode.AvalonEdit.Document.ITextSource GetTextSource(IDocument document)
+		{
+			if (document == null)
+				throw new ArgumentNullException("document");
+			return new DocumentTextSource(document);
+		}
+		
+		sealed class DocumentTextSource : ICSharpCode.AvalonEdit.Document.ITextSource
+		{
+			readonly IDocument document;
+			
+			public DocumentTextSource(IDocument document)
+			{
+				this.document = document;
+			}
+			
+			public event EventHandler TextChanged {
+				add    { document.TextChanged += value; }
+				remove { document.TextChanged -= value; }
+			}
+			
+			public string Text {
+				get { return document.Text; }
+			}
+			
+			public int TextLength {
+				get { return document.TextLength; }
+			}
+			
+			public char GetCharAt(int offset)
+			{
+				return document.GetCharAt(offset);
+			}
+			
+			public string GetText(int offset, int length)
+			{
+				return document.GetText(offset, length);
+			}
+		}
+		#endregion
+	}
+}
diff --git a/src/Main/Base/Project/Src/TextEditor/Gui/Editor/CodeCompletionBinding.cs b/src/Main/Base/Project/Src/TextEditor/Gui/Editor/CodeCompletionBinding.cs
index 63d86fe116..b76ec9d94a 100644
--- a/src/Main/Base/Project/Src/TextEditor/Gui/Editor/CodeCompletionBinding.cs
+++ b/src/Main/Base/Project/Src/TextEditor/Gui/Editor/CodeCompletionBinding.cs
@@ -189,8 +189,9 @@ namespace ICSharpCode.SharpDevelop.DefaultEditor.Gui.Editor
 				case ' ':
 					if (CodeCompletionOptions.KeywordCompletionEnabled) {
 						string word = editor.GetWordBeforeCaret();
-						if (word != null) {
-							return HandleKeyword(editor, word) ? CodeCompletionKeyPressResult.Completed : CodeCompletionKeyPressResult.None;
+						if (!string.IsNullOrEmpty(word)) {
+							if (HandleKeyword(editor, word))
+								return CodeCompletionKeyPressResult.Completed;
 						}
 					}
 					break;
diff --git a/src/Main/Base/Project/Src/TextEditor/ITextEditor.cs b/src/Main/Base/Project/Src/TextEditor/ITextEditor.cs
index 28813af114..8e6ebfbf3f 100644
--- a/src/Main/Base/Project/Src/TextEditor/ITextEditor.cs
+++ b/src/Main/Base/Project/Src/TextEditor/ITextEditor.cs
@@ -43,7 +43,6 @@ namespace ICSharpCode.SharpDevelop
 		[Obsolete]
 		void ShowCompletionWindow(ICSharpCode.TextEditor.Gui.CompletionWindow.ICompletionDataProvider provider, char ch);
 		void ShowCompletionWindow(ICompletionItemList data);
-		string GetWordBeforeCaret();
 	}
 	
 	public interface ITextEditorCaret
diff --git a/src/Main/ICSharpCode.SharpDevelop.Dom/Project/Src/Refactoring/IDocument.cs b/src/Main/ICSharpCode.SharpDevelop.Dom/Project/Src/Refactoring/IDocument.cs
index 2429b42039..40fd2b2ac0 100644
--- a/src/Main/ICSharpCode.SharpDevelop.Dom/Project/Src/Refactoring/IDocument.cs
+++ b/src/Main/ICSharpCode.SharpDevelop.Dom/Project/Src/Refactoring/IDocument.cs
@@ -20,6 +20,7 @@ namespace ICSharpCode.SharpDevelop.Dom.Refactoring
 		int TextLength { get; }
 		int TotalNumberOfLines { get; }
 		string Text { get; set; }
+		event EventHandler TextChanged;
 		
 		/// <summary>
 		/// Gets the document line with the specified number.