made it easier to change the default log formatter

ExtremelySimpleLogger/ConsoleSink.cs

@@ -47,7 +47,7 @@ namespace ExtremelySimpleLogger {
         }
 
         /// <summary>
-        /// Logs the given message, which has already been formatted using <see cref="Sink.Formatter"/>.
+        /// Logs the given message, which has already been formatted using <see cref="Sink.Formatter"/> or <see cref="Logger.DefaultFormatter"/>.
         /// </summary>
         /// <param name="logger">The logger that the message was passed to</param>
         /// <param name="level">The importance level of this message</param>

ExtremelySimpleLogger/DirectorySink.cs

@@ -85,7 +85,7 @@ namespace ExtremelySimpleLogger {
         }
 
         /// <summary>
-        /// Logs the given message, which has already been formatted using <see cref="Sink.Formatter"/>.
+        /// Logs the given message, which has already been formatted using <see cref="Sink.Formatter"/> or <see cref="Logger.DefaultFormatter"/>.
         /// </summary>
         /// <param name="logger">The logger that the message was passed to</param>
         /// <param name="level">The importance level of this message</param>

ExtremelySimpleLogger/FileSink.cs

@@ -65,7 +65,7 @@ namespace ExtremelySimpleLogger {
         }
 
         /// <summary>
-        /// Logs the given message, which has already been formatted using <see cref="Sink.Formatter"/>.
+        /// Logs the given message, which has already been formatted using <see cref="Sink.Formatter"/> or <see cref="Logger.DefaultFormatter"/>.
         /// </summary>
         /// <param name="logger">The logger that the message was passed to</param>
         /// <param name="level">The importance level of this message</param>

ExtremelySimpleLogger/Logger.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Text;
 
 namespace ExtremelySimpleLogger {
     /// <summary>
@@ -18,11 +19,16 @@ namespace ExtremelySimpleLogger {
         /// </summary>
         public LogLevel MinimumLevel { get; set; } = LogLevel.Trace;
         /// <summary>
+        /// The <see cref="LogFormatter"/> with which log messages should be formatted by a <see cref="Sink"/> if its <see cref="Sink.Formatter"/> is <see langword="null"/>.
+        /// By default, <see cref="FormatDefault"/> is used.
+        /// </summary>
+        public LogFormatter DefaultFormatter { get; set; } = Logger.FormatDefault;
+        /// <summary>
         /// If this property is set to <code>false</code>, this logger will not log any messages.
         /// </summary>
         public bool IsEnabled { get; set; } = true;
         /// <summary>
-        /// The name of this logger. This name is used in <see cref="Sink.FormatDefault"/> by default.
+        /// The name of this logger. This name is used in <see cref="FormatDefault"/> by default.
         /// </summary>
         public string Name { get; set; }
 
@@ -97,5 +103,44 @@ namespace ExtremelySimpleLogger {
                 sink.Dispose();
         }
 
+        /// <summary>
+        /// The default formatter for logging messages, which is <see cref="DefaultFormatter"/>'s initial value.
+        /// By default, messages are laid out as follows:
+        /// <code>
+        /// [Date and time] [Logger name, if set] [Log level] Message
+        ///    Exception, if set
+        /// </code>
+        /// </summary>
+        /// <param name="logger">The logger that the message was passed to</param>
+        /// <param name="level">The importance level of this message</param>
+        /// <param name="message">The message</param>
+        /// <param name="e">An optional exception whose stack trace will be appended to the message</param>
+        /// <returns>A formatted string to log</returns>
+        public static string FormatDefault(Logger logger, LogLevel level, object message, Exception e = null) {
+            var builder = new StringBuilder();
+            // date
+            builder.Append($"[{DateTime.Now}] ");
+            // logger name
+            if (!string.IsNullOrEmpty(logger.Name))
+                builder.Append($"[{logger.Name}] ");
+            // log level
+            builder.Append($"[{level}] ");
+            // message
+            builder.Append(message);
+            // stack trace
+            if (e != null)
+                builder.Append($"\n{e}");
+            return builder.ToString();
         }
+
+    }
+
+    /// <summary>
+    /// A delegate method used by <see cref="Sink.Formatter"/> and <see cref="Logger.DefaultFormatter"/>.
+    /// </summary>
+    /// <param name="logger">The logger that the message was passed to</param>
+    /// <param name="level">The importance level of this message</param>
+    /// <param name="message">The message</param>
+    /// <param name="e">An optional exception whose stack trace will be appended to the message</param>
+    public delegate string LogFormatter(Logger logger, LogLevel level, object message, Exception e = null);
 }

ExtremelySimpleLogger/Sink.cs

@@ -12,8 +12,8 @@ namespace ExtremelySimpleLogger {
         /// </summary>
         public LogLevel MinimumLevel { get; set; } = LogLevel.Trace;
         /// <summary>
-        /// The <see cref="LogFormatter"/> with which this message should be formatted.
+        /// The <see cref="LogFormatter"/> with which log messages should be formatted.
-        /// By default, <see cref="FormatDefault"/> is used.
+        /// <see cref="Logger.DefaultFormatter"/> is used if this is <see langword="null"/>.
         /// </summary>
         public LogFormatter Formatter { get; set; }
         /// <summary>
@@ -21,13 +21,6 @@ namespace ExtremelySimpleLogger {
         /// </summary>
         public bool IsEnabled { get; set; } = true;
 
-        /// <summary>
-        /// Initializes a new sink with the default settings.
-        /// </summary>
-        public Sink() {
-            this.Formatter = this.FormatDefault;
-        }
-
         /// <summary>
         /// Logs a message in the way specified by the sink's implementation.
         /// </summary>
@@ -36,61 +29,22 @@ namespace ExtremelySimpleLogger {
         /// <param name="message">The message</param>
         /// <param name="e">An optional exception whose stack trace will be appended to the message</param>
         public virtual void Log(Logger logger, LogLevel level, object message, Exception e = null) {
-            this.Log(logger, level, this.Formatter.Invoke(logger, level, message, e));
+            var formatter = this.Formatter ?? logger.DefaultFormatter;
+            this.Log(logger, level, formatter.Invoke(logger, level, message, e));
         }
 
         /// <summary>
-        /// Logs the given message, which has already been formatted using <see cref="Formatter"/>.
+        /// Logs the given message, which has already been formatted using <see cref="Formatter"/> or <see cref="Logger.DefaultFormatter"/>.
         /// </summary>
         /// <param name="logger">The logger that the message was passed to</param>
         /// <param name="level">The importance level of this message</param>
         /// <param name="s">The message to log</param>
         protected abstract void Log(Logger logger, LogLevel level, string s);
 
-        /// <summary>
-        /// The default formatter for logging messages.
-        /// By default, messages are laid out as follows:
-        /// <code>
-        /// [Date and time] [Logger name, if set] [Log level] Message
-        ///    Exception, if set
-        /// </code>
-        /// </summary>
-        /// <param name="logger">The logger that the message was passed to</param>
-        /// <param name="level">The importance level of this message</param>
-        /// <param name="message">The message</param>
-        /// <param name="e">An optional exception whose stack trace will be appended to the message</param>
-        /// <returns>A formatted string to log</returns>
-        protected virtual string FormatDefault(Logger logger, LogLevel level, object message, Exception e = null) {
-            var builder = new StringBuilder();
-            // date
-            builder.Append($"[{DateTime.Now}] ");
-            // logger name
-            if (!string.IsNullOrEmpty(logger.Name))
-                builder.Append($"[{logger.Name}] ");
-            // log level
-            builder.Append($"[{level}] ");
-            // message
-            builder.Append(message);
-            // stack trace
-            if (e != null)
-                builder.Append($"\n{e}");
-            return builder.ToString();
-        }
-
-        /// <summary>
-        /// A delegate method used by <see cref="Sink.Formatter"/>.
-        /// </summary>
-        /// <param name="logger">The logger that the message was passed to</param>
-        /// <param name="level">The importance level of this message</param>
-        /// <param name="message">The message</param>
-        /// <param name="e">An optional exception whose stack trace will be appended to the message</param>
-        public delegate string LogFormatter(Logger logger, LogLevel level, object message, Exception e = null);
-
         /// <summary>
         /// Disposes this sink, freeing all of the resources it uses.
         /// </summary>
-        public virtual void Dispose() {
+        public virtual void Dispose() {}
-        }
 
     }
 }

ExtremelySimpleLogger/StringSink.cs

@@ -31,7 +31,7 @@ namespace ExtremelySimpleLogger {
         private readonly StringBuilder builder = new StringBuilder();
 
         /// <summary>
-        /// Logs the given message, which has already been formatted using <see cref="Sink.Formatter"/>.
+        /// Logs the given message, which has already been formatted using <see cref="Sink.Formatter"/> or <see cref="Logger.DefaultFormatter"/>.
         /// </summary>
         /// <param name="logger">The logger that the message was passed to</param>
         /// <param name="level">The importance level of this message</param>