Make HighlightingRule extensible so rules aren't required to use Regex

ICSharpCode.AvalonEdit/Highlighting/HighlightingEngine.cs

@@ -116,19 +116,19 @@ void HighlightLineInternal()
 			position = 0;
 			ResetColorStack();
 			HighlightingRuleSet currentRuleSet = this.CurrentRuleSet;
-			Stack<Match[]> storedMatchArrays = new Stack<Match[]>();
-			Match[] matches = AllocateMatchArray(currentRuleSet.Spans.Count);
-			Match endSpanMatch = null;
+			Stack<RuleMatch[]> storedMatchArrays = new Stack<RuleMatch[]>();
+			RuleMatch[] matches = AllocateMatchArray(currentRuleSet.Spans.Count);
+			RuleMatch endSpanMatch = null;
 
 			while (true) {
 				for (int i = 0; i < matches.Length; i++) {
 					if (matches[i] == null || (matches[i].Success && matches[i].Index < position))
-						matches[i] = currentRuleSet.Spans[i].StartExpression.Match(lineText, position);
+						matches[i] = currentRuleSet.Spans[i].GetStartMatch(lineText, position);
 				}
 				if (endSpanMatch == null && !spanStack.IsEmpty)
-					endSpanMatch = spanStack.Peek().EndExpression.Match(lineText, position);
+					endSpanMatch = spanStack.Peek().GetEndMatch(lineText, position);
 
-				Match firstMatch = Minimum(matches, endSpanMatch);
+				RuleMatch firstMatch = Minimum(matches, endSpanMatch);
 				if (firstMatch == null)
 					break;
 
@@ -191,14 +191,14 @@ void HighlightNonSpans(int until)
 			if (position == until)
 				return;
 			if (highlightedLine != null) {
-				IList<HighlightingRule> rules = CurrentRuleSet.Rules;
-				Match[] matches = AllocateMatchArray(rules.Count);
+				IList<IHighlightingRule> rules = CurrentRuleSet.Rules;
+				RuleMatch[] matches = AllocateMatchArray(rules.Count);
 				while (true) {
 					for (int i = 0; i < matches.Length; i++) {
 						if (matches[i] == null || (matches[i].Success && matches[i].Index < position))
-							matches[i] = rules[i].Regex.Match(lineText, position, until - position);
+							matches[i] = rules[i].GetMatch(lineText, position, until - position, highlightedLine.DocumentLine.LineNumber);
 					}
-					Match firstMatch = Minimum(matches, null);
+					RuleMatch firstMatch = Minimum(matches, null);
 					if (firstMatch == null)
 						break;
 
@@ -208,7 +208,7 @@ void HighlightNonSpans(int until)
 						throw new InvalidOperationException(
 							"A highlighting rule matched 0 characters, which would cause an endless loop.\n" +
 							"Change the highlighting definition so that the rule matches at least one character.\n" +
-							"Regex: " + rules[ruleIndex].Regex);
+							rules[ruleIndex].RuleInfo);
 					}
 					PushColor(rules[ruleIndex].Color);
 					position = firstMatch.Index + firstMatch.Length;
@@ -297,10 +297,10 @@ void PopAllColors()
 		/// <summary>
 		/// Returns the first match from the array or endSpanMatch.
 		/// </summary>
-		static Match Minimum(Match[] arr, Match endSpanMatch)
+		static RuleMatch Minimum(RuleMatch[] arr, RuleMatch endSpanMatch)
 		{
-			Match min = null;
-			foreach (Match v in arr) {
+			RuleMatch min = null;
+			foreach (RuleMatch v in arr) {
 				if (v.Success && (min == null || v.Index < min.Index))
 					min = v;
 			}
@@ -310,12 +310,12 @@ static Match Minimum(Match[] arr, Match endSpanMatch)
 				return min;
 		}
 
-		static Match[] AllocateMatchArray(int count)
+		static RuleMatch[] AllocateMatchArray(int count)
 		{
 			if (count == 0)
-				return Empty<Match>.Array;
+				return Empty<RuleMatch>.Array;
 			else
-				return new Match[count];
+				return new RuleMatch[count];
 		}
 		#endregion
 	}

ICSharpCode.AvalonEdit/Highlighting/HighlightingRule.cs

@@ -25,7 +25,7 @@ namespace ICSharpCode.AvalonEdit.Highlighting
 	/// A highlighting rule.
 	/// </summary>
 	[Serializable]
-	public class HighlightingRule
+	public class HighlightingRule : IHighlightingRule
 	{
 		/// <summary>
 		/// Gets/Sets the regular expression for the rule.
@@ -37,6 +37,15 @@ public class HighlightingRule
 		/// </summary>
 		public HighlightingColor Color { get; set; }
 
+		/// <inheritdoc/>
+		public string RuleInfo => $"Regex: {Regex}";
+
+		/// <inheritdoc/>
+		public RuleMatch GetMatch(string input, int beginning, int length, int lineNumber)
+		{
+			return RuleMatch.FromRegexMatch(Regex.Match(input, beginning, length));
+		}
+
 		/// <inheritdoc/>
 		public override string ToString()
 		{

ICSharpCode.AvalonEdit/Highlighting/HighlightingRuleSet.cs

@@ -35,7 +35,7 @@ public class HighlightingRuleSet
 		public HighlightingRuleSet()
 		{
 			this.Spans = new NullSafeCollection<HighlightingSpan>();
-			this.Rules = new NullSafeCollection<HighlightingRule>();
+			this.Rules = new NullSafeCollection<IHighlightingRule>();
 		}
 
 		/// <summary>
@@ -51,7 +51,7 @@ public HighlightingRuleSet()
 		/// <summary>
 		/// Gets the list of rules.
 		/// </summary>
-		public IList<HighlightingRule> Rules { get; private set; }
+		public IList<IHighlightingRule> Rules { get; private set; }
 
 		/// <inheritdoc/>
 		public override string ToString()

ICSharpCode.AvalonEdit/Highlighting/HighlightingSpan.cs

@@ -70,6 +70,28 @@ public class HighlightingSpan
 		/// </summary>
 		public bool SpanColorIncludesEnd { get; set; }
 
+		/// <summary>
+		/// Gets the match from the specified position using the <see cref="StartExpression"/> regex.
+		/// </summary>
+		/// <param name="text">The string to search for a match</param>
+		/// <param name="position">The zero-based character position at which to start the search</param>
+		/// <returns>And object that contains information about the match</returns>
+		public RuleMatch GetStartMatch(string text, int position)
+		{
+			return RuleMatch.FromRegexMatch(StartExpression.Match(text, position));
+		}
+
+		/// <summary>
+		/// Gets the match from the specified position using the <see cref="EndExpression"/> regex.
+		/// </summary>
+		/// <param name="text">The string to search for a match</param>
+		/// <param name="position">The zero-based character position at which to start the search</param>
+		/// <returns>And object that contains information about the match</returns>
+		public RuleMatch GetEndMatch(string text, int position)
+		{
+			return RuleMatch.FromRegexMatch(EndExpression.Match(text, position));
+		}
+
 		/// <inheritdoc/>
 		public override string ToString()
 		{

ICSharpCode.AvalonEdit/Highlighting/IHighlightingRule.cs

@@ -0,0 +1,47 @@
+// Copyright (c) 2014 AlphaSierraPapa for the SharpDevelop Team
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+namespace ICSharpCode.AvalonEdit.Highlighting
+{
+	/// <summary>
+	/// Interface of a highlighting rule
+	/// </summary>
+	public interface IHighlightingRule
+	{
+		/// <summary>
+		/// Gets the first match for the rule
+		/// </summary>
+		/// <param name="input">The string to search for a match.</param>
+		/// <param name="beginning">The zero-based character position in the input string that defines the leftmost 
+		/// position to be searched.</param>
+		/// <param name="length">The number of characters in the substring to include in the search.</param>
+		/// <param name="lineNumber">The line number of the <paramref name="input"/> string.</param>
+		/// <returns>An object that contains information about the match.</returns>
+		RuleMatch GetMatch(string input, int beginning, int length, int lineNumber);
+
+		/// <summary>
+		/// Gets the highlighting color.
+		/// </summary>
+		HighlightingColor Color { get; }
+
+		/// <summary>
+		/// Info about rule. Used to help figure out why rule failed
+		/// </summary>
+		string RuleInfo { get; }
+	}
+}

ICSharpCode.AvalonEdit/Highlighting/RuleMatch.cs

@@ -0,0 +1,62 @@
+// Copyright (c) 2014 AlphaSierraPapa for the SharpDevelop Team
+// 
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this
+// software and associated documentation files (the "Software"), to deal in the Software
+// without restriction, including without limitation the rights to use, copy, modify, merge,
+// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
+// to whom the Software is furnished to do so, subject to the following conditions:
+// 
+// The above copyright notice and this permission notice shall be included in all copies or
+// substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
+// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
+// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+using System.Text.RegularExpressions;
+
+namespace ICSharpCode.AvalonEdit.Highlighting
+{
+	/// <summary>
+	/// And object that contains information about a rule's match
+	/// </summary>
+	public class RuleMatch
+	{
+		/// <summary>
+		/// Creates a new RuleMatch instance.
+		/// </summary>
+		public RuleMatch() { }
+
+		/// <summary>
+		/// Gets a value indicating whether the match was successful.
+		/// </summary>
+		public bool Success { get; set; }
+
+		/// <summary>
+		/// The position in the original string where the first character of captured substring was found.
+		/// </summary>
+		public int Index { get; set; }
+
+		/// <summary>
+		/// The length of the captured substring.
+		/// </summary>
+		public int Length { get; set; }
+
+		/// <summary>
+		/// Creates a new RuleMatch instance from a <see cref="Match"/> instance.
+		/// </summary>
+		/// <param name="match">Match to use</param>
+		/// <returns>RuleMatch instance built from match parameter</returns>
+		public static RuleMatch FromRegexMatch(Match match)
+		{
+			return new RuleMatch() {
+				Success = match.Success,
+				Index = match.Index,
+				Length = match.Length,
+			};
+		}
+	}
+}

ICSharpCode.AvalonEdit/Highlighting/Xshd/XmlHighlightingDefinition.cs

@@ -172,7 +172,7 @@ public object VisitRuleSet(XshdRuleSet ruleSet)
 						if (span != null) {
 							rs.Spans.Add(span);
 						} else {
-							HighlightingRule elementRule = o as HighlightingRule;
+							IHighlightingRule elementRule = o as IHighlightingRule;
 							if (elementRule != null) {
 								rs.Rules.Add(elementRule);
 							}