src/Tools/VSCode/src/channel.scala

   }
 
 
   /* write message */
 
-  def write(json: JSON.T)
+  def write(json: JSON.T): Unit =
   {
     val msg = JSON.Format(json)
     val content = UTF8.bytes(msg)
     val n = content.length
     val header = UTF8.bytes("Content-Length: " + n + "\r\n\r\n")

   /* display message */
 
   def display_message(message_type: Int, msg: String, show: Boolean = true): Unit =
     write(LSP.DisplayMessage(message_type, Output.clean_yxml(msg), show))
 
-  def error_message(msg: String) { display_message(LSP.MessageType.Error, msg, true) }
-  def warning(msg: String) { display_message(LSP.MessageType.Warning, msg, true) }
-  def writeln(msg: String) { display_message(LSP.MessageType.Info, msg, true) }
+  def error_message(msg: String): Unit = display_message(LSP.MessageType.Error, msg, true)
+  def warning(msg: String): Unit = display_message(LSP.MessageType.Warning, msg, true)
+  def writeln(msg: String): Unit = display_message(LSP.MessageType.Info, msg, true)
 
-  def log_error_message(msg: String) { display_message(LSP.MessageType.Error, msg, false) }
-  def log_warning(msg: String) { display_message(LSP.MessageType.Warning, msg, false) }
-  def log_writeln(msg: String) { display_message(LSP.MessageType.Info, msg, false) }
+  def log_error_message(msg: String): Unit = display_message(LSP.MessageType.Error, msg, false)
+  def log_warning(msg: String): Unit = display_message(LSP.MessageType.Warning, msg, false)
+  def log_writeln(msg: String): Unit = display_message(LSP.MessageType.Info, msg, false)
 
   object Error_Logger extends Logger
   {
-    def apply(msg: => String) { log_error_message(msg) }
+    def apply(msg: => String): Unit = log_error_message(msg)
   }
 
 
   /* progress */