Provide an easy way to print stuff before displaying the prompt.

git-svn-id: https://arducopter.googlecode.com/svn/trunk@545 f9c3cf11-9bcb-44bc-f272-b75c42450872

libraries/AP_Common/examples/menu/menu.pde

@@ -18,7 +18,14 @@ menu_test(uint8_t argc, const Menu::arg *argv)
 	}
 }
 
+int
+menu_auto(uint8_t argc, const Menu::arg *argv)
+{
+	Serial.println("auto text");
+}
+
 const struct Menu::command top_menu_commands[] PROGMEM = {
+        {"*",                           menu_auto},
 	{"test",			menu_test},
 };
 

libraries/AP_Common/include/menu.h

@@ -26,7 +26,17 @@ public:
 	/// Note that the array of menu commands is expected to be in program 
 	/// memory.
 	struct command {
-		const char	command[MENU_COMMAND_MAX];						///< name of the command
+		/// Name of the command, as typed or received.
+		/// Command names are limited in size to keep this structure compact.
+		/// If the first command in the menu is named '*', it will be called
+		/// each time before printing the prompt.
+		const char	command[MENU_COMMAND_MAX];
+
+		/// The function to call when the command is received.
+		/// The \a argc argument will be at least 1, and no more than
+		/// MENU_ARGS_MAX.  The argv array will be populated with
+		/// arguments typed/received up to MENU_ARGS_MAX.  The command
+		/// name will always be in argv[0].
 		int			(*func)(uint8_t argc, const struct arg *argv);	///< callback function
 	};
 
@@ -42,7 +52,16 @@ public:
 	void				run(void);
 	
 private:
+	/// Implements the default 'help' command
+	///
 	void				_help(void);					///< implements the 'help' command
+
+	/// calls the function for the n'th menu item
+	///
+	/// @param n			Index for the menu item to call
+	/// @param argc			Number of arguments prepared for the menu item
+	///
+	int					_call(uint8_t n, uint8_t argc);
 	const char			*_prompt;						///< prompt to display
 	const command		*_commands;						///< array of commands
 	const uint8_t		_entries;						///< size of the menu

libraries/AP_Common/menu.cpp

@@ -31,11 +31,16 @@ Menu::run(void)
 	uint8_t		len, i, ret;
 	uint8_t		argc;
 	int			c;
-	func		fn;
 		
 	// loop performing commands
 	for (;;) {
 
+		// if the first command is called '*', call it before displaying the menu
+		if ("*", _commands[0].command) {
+			if (-2 == _call(0, 0))
+				return;
+		}
+	
 		// loop reading characters from the input
 		len = 0;
 		Serial.printf("%S] ", _prompt);
@@ -83,8 +88,7 @@ Menu::run(void)
 		// look for a command matching the first word (note that it may be empty)
 		for (i = 0; i < _entries; i++) {
 			if (!strcmp_P(_argv[0].str, _commands[i].command)) {
-				fn = (func)pgm_read_word(&_commands[i].func);
-				ret = fn(argc, &_argv[0]);
+				ret = _call(i, argc);
 				if (-2 == ret)
 					return;
 			}
@@ -106,3 +110,13 @@ Menu::_help(void)
 	for (i = 0; i < _entries; i++)
 		Serial.printf("  %S\n", _commands[i].command);
 }
+
+// run the n'th command in the menu
+int
+Menu::_call(uint8_t n, uint8_t argc)
+{
+	func		fn;
+
+	fn = (func)pgm_read_word(&_commands[n].func);
+	return(fn(argc, &_argv[0]));
+}