delegate interface.patch

Index: src/Core/LogImpl.cs
===================================================================
--- src/Core/LogImpl.cs        (revision 1466376)
+++ src/Core/LogImpl.cs	(working copy)
@@ -170,6 +170,15 @@
 			Logger.Log(ThisDeclaringType, m_levelDebug, message, null);
 		}
 
+		virtual public void Debug(LogMessageCallback messageCallback)
+		{
+			if (IsDebugEnabled)
+			{
+				Logger.Log(ThisDeclaringType, m_levelDebug, messageCallback(), null);
+			}
+		}
+
+
 		/// <summary>
 		/// Logs a message object with the <c>DEBUG</c> level
 		/// </summary>
@@ -367,6 +376,14 @@
 		{
 			Logger.Log(ThisDeclaringType, m_levelInfo, message, null);
 		}
+
+		virtual public void Info(LogMessageCallback messageCallback)
+		{
+			if (IsInfoEnabled)
+			{
+				Logger.Log(ThisDeclaringType, m_levelInfo, messageCallback(), null);
+			}
+		}
   
 		/// <summary>
 		/// Logs a message object with the <c>INFO</c> level.
@@ -565,6 +582,14 @@
 		{
 			Logger.Log(ThisDeclaringType, m_levelWarn, message, null);
 		}
+
+		virtual public void Warn(LogMessageCallback messageCallback)
+		{
+			if (IsWarnEnabled)
+			{
+				Logger.Log(ThisDeclaringType, m_levelWarn, messageCallback(), null);
+			}
+		}
   
 		/// <summary>
 		/// Logs a message object with the <c>WARN</c> level
@@ -764,6 +789,14 @@
 			Logger.Log(ThisDeclaringType, m_levelError, message, null);
 		}
 
+		virtual public void Error(LogMessageCallback messageCallback)
+		{
+			if (IsErrorEnabled)
+			{
+				Logger.Log(ThisDeclaringType, m_levelError, messageCallback(), null);
+			}
+		}
+
 		/// <summary>
 		/// Logs a message object with the <c>ERROR</c> level
 		/// </summary>
@@ -961,6 +994,14 @@
 		{
 			Logger.Log(ThisDeclaringType, m_levelFatal, message, null);
 		}
+
+		virtual public void Fatal(LogMessageCallback messageCallback)
+		{
+			if (IsFatalEnabled)
+			{
+				Logger.Log(ThisDeclaringType, m_levelFatal, messageCallback(), null);
+			}
+		}
   
 		/// <summary>
 		/// Logs a message object with the <c>FATAL</c> level
Index: src/ILog.cs
===================================================================
--- src/ILog.cs	(revision 1466376)
+++ src/ILog.cs	(working copy)
@@ -91,6 +91,8 @@
 		/// <seealso cref="M:Debug(object,Exception)"/>
 		/// <seealso cref="IsDebugEnabled"/>
 		void Debug(object message);
+
+		void Debug(LogMessageCallback messageCallback);
   
 		/// <summary>
 		/// Log a message object with the <see cref="Level.Debug"/> level including
@@ -244,7 +246,9 @@
 		/// <seealso cref="M:Info(object,Exception)"/>
 		/// <seealso cref="IsInfoEnabled"/>
 		void Info(object message);
-  
+
+		void Info(LogMessageCallback messageCallback);
+
 		/// <summary>
 		/// Logs a message object with the <c>INFO</c> level including
 		/// the stack trace of the <see cref="Exception"/> passed
@@ -397,7 +401,9 @@
 		/// <seealso cref="M:Warn(object,Exception)"/>
 		/// <seealso cref="IsWarnEnabled"/>
 		void Warn(object message);
-  
+
+		void Warn(LogMessageCallback messageCallback);
+
 		/// <summary>
 		/// Log a message object with the <see cref="Level.Warn"/> level including
 		/// the stack trace of the <see cref="Exception"/> passed
@@ -551,6 +557,8 @@
 		/// <seealso cref="IsErrorEnabled"/>
 		void Error(object message);
 
+		void Error(LogMessageCallback messageCallback);
+
 		/// <summary>
 		/// Log a message object with the <see cref="Level.Error"/> level including
 		/// the stack trace of the <see cref="Exception"/> passed
@@ -703,7 +711,9 @@
 		/// <seealso cref="M:Fatal(object,Exception)"/>
 		/// <seealso cref="IsFatalEnabled"/>
 		void Fatal(object message);
-  
+
+		void Fatal(LogMessageCallback messageCallback);
+		
 		/// <summary>
 		/// Log a message object with the <see cref="Level.Fatal"/> level including
 		/// the stack trace of the <see cref="Exception"/> passed
@@ -957,4 +967,6 @@
 		/// <seealso cref="ILog.IsDebugEnabled"/>
 		bool IsFatalEnabled { get; }
 	}
+
+	public delegate string LogMessageCallback();
 }