bool MarkTokensInLine(IDocument document, int lineNumber, ref bool spanChanged)
		{
			currentLineNumber = lineNumber;
			bool processNextLine = false;
			LineSegment previousLine = (lineNumber > 0 ? document.GetLineSegment(lineNumber - 1) : null);
			
			currentSpanStack = ((previousLine != null && previousLine.HighlightSpanStack != null) ? previousLine.HighlightSpanStack.Clone() : null);
			if (currentSpanStack != null) {
				while (!currentSpanStack.IsEmpty && currentSpanStack.Peek().StopEOL) {
					currentSpanStack.Pop();
				}
				if (currentSpanStack.IsEmpty) {
					currentSpanStack = null;
				}
			}
			
			currentLine = (LineSegment)document.LineSegmentCollection[lineNumber];
			
			if (currentLine.Length == -1) { // happens when buffer is empty !
				return false;
			}
			
			List<TextWord> words = ParseLine(document);
			
			if (currentSpanStack != null && currentSpanStack.IsEmpty) {
				currentSpanStack = null;
			}
			
			// Check if the span state has changed, if so we must re-render the next line
			// This check may seem utterly complicated but I didn't want to introduce any function calls
			// or allocations here for perf reasons.
			if(currentLine.HighlightSpanStack != currentSpanStack) {
				if (currentLine.HighlightSpanStack == null) {
					processNextLine = false;
					foreach (Span sp in currentSpanStack) {
						if (!sp.StopEOL) {
							spanChanged = true;
							processNextLine = true;
							break;
						}
					}
				} else if (currentSpanStack == null) {
					processNextLine = false;
					foreach (Span sp in currentLine.HighlightSpanStack) {
						if (!sp.StopEOL) {
							spanChanged = true;
							processNextLine = true;
							break;
						}
					}
				} else {
					SpanStack.Enumerator e1 = currentSpanStack.GetEnumerator();
					SpanStack.Enumerator e2 = currentLine.HighlightSpanStack.GetEnumerator();
					bool done = false;
					while (!done) {
						bool blockSpanIn1 = false;
						while (e1.MoveNext()) {
							if (!((Span)e1.Current).StopEOL) {
								blockSpanIn1 = true;
								break;
							}
						}
						bool blockSpanIn2 = false;
						while (e2.MoveNext()) {
							if (!((Span)e2.Current).StopEOL) {
								blockSpanIn2 = true;
								break;
							}
						}
						if (blockSpanIn1 || blockSpanIn2) {
							if (blockSpanIn1 && blockSpanIn2) {
								if (e1.Current != e2.Current) {
									done = true;
									processNextLine = true;
									spanChanged = true;
								}
							} else {
								spanChanged = true;
								done = true;
								processNextLine = true;
							}
						} else {
							done = true;
							processNextLine = false;
						}
					}
				}
			} else {
				processNextLine = false;
			}
			
			//// Alex: remove old words
			if (currentLine.Words!=null) currentLine.Words.Clear();
			currentLine.Words = words;
			currentLine.HighlightSpanStack = (currentSpanStack != null && !currentSpanStack.IsEmpty) ? currentSpanStack : null;
			
			return processNextLine;
		}
		List<TextWord> ParseLine(IDocument document)
		{
			List<TextWord> words = new List<TextWord>();
			HighlightColor markNext = null;
			
			currentOffset = 0;
			currentLength = 0;
			UpdateSpanStateVariables();
			
			int currentLineLength = currentLine.Length;
			int currentLineOffset = currentLine.Offset;
			
			for (int i = 0; i < currentLineLength; ++i) {
				char ch = document.GetCharAt(currentLineOffset + i);
				switch (ch) {
					case '\n':
					case '\r':
						PushCurWord(document, ref markNext, words);
						++currentOffset;
						break;
					case ' ':
						PushCurWord(document, ref markNext, words);
						if (activeSpan != null && activeSpan.Color.HasBackground) {
							words.Add(new TextWord.SpaceTextWord(activeSpan.Color));
						} else {
							words.Add(TextWord.Space);
						}
						++currentOffset;
						break;
					case '\t':
						PushCurWord(document, ref markNext, words);
						if (activeSpan != null && activeSpan.Color.HasBackground) {
							words.Add(new TextWord.TabTextWord(activeSpan.Color));
						} else {
							words.Add(TextWord.Tab);
						}
						++currentOffset;
						break;
					default:
						{
							// handle escape characters
							char escapeCharacter = '\0';
							if (activeSpan != null && activeSpan.EscapeCharacter != '\0') {
								escapeCharacter = activeSpan.EscapeCharacter;
							} else if (activeRuleSet != null) {
								escapeCharacter = activeRuleSet.EscapeCharacter;
							}
							if (escapeCharacter != '\0' && escapeCharacter == ch) {
								// we found the escape character
								if (activeSpan != null && activeSpan.End != null && activeSpan.End.Length == 1
								    && escapeCharacter == activeSpan.End[0])
								{
									// the escape character is a end-doubling escape character
									// it may count as escape only when the next character is the escape, too
									if (i + 1 < currentLineLength) {
										if (document.GetCharAt(currentLineOffset + i + 1) == escapeCharacter) {
											currentLength += 2;
											PushCurWord(document, ref markNext, words);
											++i;
											continue;
										}
									}
								} else {
									// this is a normal \-style escape
									++currentLength;
									if (i + 1 < currentLineLength) {
										++currentLength;
									}
									PushCurWord(document, ref markNext, words);
									++i;
									continue;
								}
							}
							
							// highlight digits
							if (!inSpan && (Char.IsDigit(ch) || (ch == '.' && i + 1 < currentLineLength && Char.IsDigit(document.GetCharAt(currentLineOffset + i + 1)))) && currentLength == 0) {
								bool ishex = false;
								bool isfloatingpoint = false;
								
								if (ch == '0' && i + 1 < currentLineLength && Char.ToUpper(document.GetCharAt(currentLineOffset + i + 1)) == 'X') { // hex digits
									const string hex = "0123456789ABCDEF";
									++currentLength;
									++i; // skip 'x'
									++currentLength;
									ishex = true;
									while (i + 1 < currentLineLength && hex.IndexOf(Char.ToUpper(document.GetCharAt(currentLineOffset + i + 1))) != -1) {
										++i;
										++currentLength;
									}
								} else {
									++currentLength;
									while (i + 1 < currentLineLength && Char.IsDigit(document.GetCharAt(currentLineOffset + i + 1))) {
										++i;
										++currentLength;
									}
								}
								if (!ishex && i + 1 < currentLineLength && document.GetCharAt(currentLineOffset + i + 1) == '.') {
									isfloatingpoint = true;
									++i;
									++currentLength;
									while (i + 1 < currentLineLength && Char.IsDigit(document.GetCharAt(currentLineOffset + i + 1))) {
										++i;
										++currentLength;
									}
								}
								
								if (i + 1 < currentLineLength && Char.ToUpper(document.GetCharAt(currentLineOffset + i + 1)) == 'E') {
									isfloatingpoint = true;
									++i;
									++currentLength;
									if (i + 1 < currentLineLength && (document.GetCharAt(currentLineOffset + i + 1) == '+' || document.GetCharAt(currentLine.Offset + i + 1) == '-')) {
										++i;
										++currentLength;
									}
									while (i + 1 < currentLine.Length && Char.IsDigit(document.GetCharAt(currentLineOffset + i + 1))) {
										++i;
										++currentLength;
									}
								}
								
								if (i + 1 < currentLine.Length) {
									char nextch = Char.ToUpper(document.GetCharAt(currentLineOffset + i + 1));
									if (nextch == 'F' || nextch == 'M' || nextch == 'D') {
										isfloatingpoint = true;
										++i;
										++currentLength;
									}
								}
								
								if (!isfloatingpoint) {
									bool isunsigned = false;
									if (i + 1 < currentLineLength && Char.ToUpper(document.GetCharAt(currentLineOffset + i + 1)) == 'U') {
										++i;
										++currentLength;
										isunsigned = true;
									}
									if (i + 1 < currentLineLength && Char.ToUpper(document.GetCharAt(currentLineOffset + i + 1)) == 'L') {
										++i;
										++currentLength;
										if (!isunsigned && i + 1 < currentLineLength && Char.ToUpper(document.GetCharAt(currentLineOffset + i + 1)) == 'U') {
											++i;
											++currentLength;
										}
									}
								}
								
								words.Add(new TextWord(document, currentLine, currentOffset, currentLength, DigitColor, false));
								currentOffset += currentLength;
								currentLength = 0;
								continue;
							}

							// Check for SPAN ENDs
							if (inSpan) {
								if (activeSpan.End != null && activeSpan.End.Length > 0) {
									if (MatchExpr(currentLine, activeSpan.End, i, document, activeSpan.IgnoreCase)) {
										PushCurWord(document, ref markNext, words);
										string regex = GetRegString(currentLine, activeSpan.End, i, document);
										currentLength += regex.Length;
										words.Add(new TextWord(document, currentLine, currentOffset, currentLength, activeSpan.EndColor, false));
										currentOffset += currentLength;
										currentLength = 0;
										i += regex.Length - 1;
										currentSpanStack.Pop();
										UpdateSpanStateVariables();
										continue;
									}
								}
							}
							
							// check for SPAN BEGIN
							if (activeRuleSet != null) {
								foreach (Span span in activeRuleSet.Spans) {
									if ((!span.IsBeginSingleWord || currentLength == 0)
									    && (!span.IsBeginStartOfLine.HasValue || span.IsBeginStartOfLine.Value == (currentLength == 0 && words.TrueForAll(delegate(TextWord textWord) { return textWord.Type != TextWordType.Word; })))
									    && MatchExpr(currentLine, span.Begin, i, document, activeRuleSet.IgnoreCase)) {
										PushCurWord(document, ref markNext, words);
										string regex = GetRegString(currentLine, span.Begin, i, document);
										
										if (!OverrideSpan(regex, document, words, span, ref i)) {
											currentLength += regex.Length;
											words.Add(new TextWord(document, currentLine, currentOffset, currentLength, span.BeginColor, false));
											currentOffset += currentLength;
											currentLength = 0;
											
											i += regex.Length - 1;
											if (currentSpanStack == null) {
												currentSpanStack = new SpanStack();
											}
											currentSpanStack.Push(span);
											span.IgnoreCase = activeRuleSet.IgnoreCase;
											
											UpdateSpanStateVariables();
										}
										
										goto skip;
									}
								}
							}
							
							// check if the char is a delimiter
							if (activeRuleSet != null && (int)ch < 256 && activeRuleSet.Delimiters[(int)ch]) {
								PushCurWord(document, ref markNext, words);
								if (currentOffset + currentLength +1 < currentLine.Length) {
									++currentLength;
									PushCurWord(document, ref markNext, words);
									goto skip;
								}
							}
							
							++currentLength;
							skip: continue;
						}
				}
			}
			
			PushCurWord(document, ref markNext, words);
			
			OnParsedLine(document, currentLine, words);
			
			return words;
		}
		public virtual void MarkTokens(IDocument document)
		{
			if (Rules.Count == 0) {
				return;
			}
			
			int lineNumber = 0;
			
			while (lineNumber < document.TotalNumberOfLines) {
				LineSegment previousLine = (lineNumber > 0 ? document.GetLineSegment(lineNumber - 1) : null);
				if (lineNumber >= document.LineSegmentCollection.Count) { // may be, if the last line ends with a delimiter
					break;                                                // then the last line is not in the collection :)
				}
				
				currentSpanStack = ((previousLine != null && previousLine.HighlightSpanStack != null) ? previousLine.HighlightSpanStack.Clone() : null);
				
				if (currentSpanStack != null) {
					while (!currentSpanStack.IsEmpty && currentSpanStack.Peek().StopEOL)
					{
						currentSpanStack.Pop();
					}
					if (currentSpanStack.IsEmpty) currentSpanStack = null;
				}
				
				currentLine = (LineSegment)document.LineSegmentCollection[lineNumber];
				
				if (currentLine.Length == -1) { // happens when buffer is empty !
					return;
				}
				
				currentLineNumber = lineNumber;
				List<TextWord> words = ParseLine(document);
				// Alex: clear old words
				if (currentLine.Words != null) {
					currentLine.Words.Clear();
				}
				currentLine.Words = words;
				currentLine.HighlightSpanStack = (currentSpanStack==null || currentSpanStack.IsEmpty) ? null : currentSpanStack;
				
				++lineNumber;
			}
			document.RequestUpdate(new TextAreaUpdate(TextAreaUpdateType.WholeTextArea));
			document.CommitUpdate();
			currentLine = null;
		}