Spacing, coding standards

Marlin/Configuration_adv.h

                                               // or until outcoming filament color is not clear for filament color change
   #define FILAMENT_CHANGE_EXTRUDE_FEEDRATE 3  // Extrude filament feedrate in mm/s - must be slower than load feedrate
   #define FILAMENT_CHANGE_NOZZLE_TIMEOUT 45L  // Turn off nozzle if user doesn't change filament within this time limit in seconds
-  #define FILAMENT_CHANGE_NUMBER_OF_ALERT_BEEPS  5L             // Number of alert beeps before printer goes quiet 
-  #define STEPPER_MOTORS_DONT_TIMEOUT_DURING_FILAMENT_CHANGE    // Enable to make stepper motors hold position during filament change even if it 
-                                                                // takes longer than DEFAULT_STEPPER_DEACTIVE_TIME
+  #define FILAMENT_CHANGE_NUMBER_OF_ALERT_BEEPS  5L  // Number of alert beeps before printer goes quiet
+  #define FILAMENT_CHANGE_NO_STEPPER_TIMEOUT         // Enable to have stepper motors hold position during filament change
+                                                     // even if it takes longer than DEFAULT_STEPPER_DEACTIVE_TIME.
 #endif
 
 /******************************************************************************\

Marlin/Marlin_main.cpp

     }
   }
 
-  bool busy_doing_M600 = false;
+  static bool busy_doing_M600 = false;
 
   /**
    * M600: Pause for filament change
       #define RUNPLAN(RATE_MM_S) line_to_destination(RATE_MM_S);
     #endif
 
-    KEEPALIVE_STATE(IN_HANDLER);
-
     // Initial retract before move to filament change position
     if (code_seen('E')) destination[E_AXIS] += code_value_axis_units(E_AXIS);
     #if defined(FILAMENT_CHANGE_RETRACT_LENGTH) && FILAMENT_CHANGE_RETRACT_LENGTH > 0
     disable_e3();
     delay(100);
 
-    millis_t nozzle_timeout = millis() + FILAMENT_CHANGE_NOZZLE_TIMEOUT*1000L;
+    millis_t nozzle_timeout = millis() + FILAMENT_CHANGE_NOZZLE_TIMEOUT * 1000L;
     bool nozzle_timed_out = false;
     float temps[4];
-    int iii;
 
     // Wait for filament insert by user and press button
     lcd_filament_change_show_message(FILAMENT_CHANGE_MESSAGE_INSERT);
     wait_for_user = true;    // LCD click or M108 will clear this
     next_buzz = 0;
     runout_beep = 0;
-    for( iii=0; iii<HOTENDS; iii++)      //Save nozzle temps
-      temps[iii] = thermalManager.target_temperature[iii]; 
+    HOTEND_LOOP() temps[e] = thermalManager.target_temperature[e]; // Save nozzle temps
 
     while (wait_for_user) {
       millis_t current_ms = millis();
-      if (nozzle_timed_out == true)
+      if (nozzle_timed_out)
         lcd_filament_change_show_message(FILAMENT_CHANGE_MESSAGE_CLICK_TO_HEAT_NOZZLE);
+
       #if HAS_BUZZER 
         filament_change_beep();
-      #endif //HAS_BUZZER
+      #endif
 
       if (current_ms >= nozzle_timeout) {
-        if (nozzle_timed_out == false ) {
-          nozzle_timed_out = true;         // if the nozzle time out happens, remember we turned off the nozzles. 
-          for( iii=0; iii<HOTENDS; iii++)  // turn off all the nozzles
-            thermalManager.setTargetHotend( 0.0 , iii );
-
+        if (!nozzle_timed_out) {
+          nozzle_timed_out = true; // on nozzle timeout remember the nozzles need to be reheated
+          HOTEND_LOOP() thermalManager.setTargetHotend(0, e); // Turn off all the nozzles
           lcd_filament_change_show_message(FILAMENT_CHANGE_MESSAGE_CLICK_TO_HEAT_NOZZLE);
         }
       }
       idle(true);
     }
 
-    if (nozzle_timed_out == true ) {      // Turn nozzles back on if we turned them off.
-      for( iii=0; iii<HOTENDS; iii++)
-        thermalManager.setTargetHotend( temps[iii] , iii );
-      lcd_filament_change_show_message(FILAMENT_CHANGE_MESSAGE_WAIT_FOR_NOZZLES_TO_HEAT);
-    }
+    if (nozzle_timed_out)      // Turn nozzles back on if they were turned off
+      HOTEND_LOOP() thermalManager.setTargetHotend(temps[e], e);
 
-KEEP_CHECKING_TEMPS:
-    idle();
-    for( iii=0; iii<HOTENDS; iii++){
-      if (abs(thermalManager.degHotend(iii)-temps[iii]) > 3 ) {
-        lcd_filament_change_show_message(FILAMENT_CHANGE_MESSAGE_WAIT_FOR_NOZZLES_TO_HEAT);
-        goto KEEP_CHECKING_TEMPS;
+    // Show "wait for heating"
+    lcd_filament_change_show_message(FILAMENT_CHANGE_MESSAGE_WAIT_FOR_NOZZLES_TO_HEAT);
+
+    wait_for_heatup = true;
+    while (wait_for_heatup) {
+      idle();
+      wait_for_heatup = false;
+      HOTEND_LOOP() {
+        if (abs(thermalManager.degHotend(e) - temps[e]) > 3) {
+          wait_for_heatup = true;
+          break;
+        }
       }
     }
 
+    // Show "insert filament"
+    if (nozzle_timed_out)
+      lcd_filament_change_show_message(FILAMENT_CHANGE_MESSAGE_INSERT);
+
     wait_for_user = true;    // LCD click or M108 will clear this
     next_buzz = 0;
     runout_beep = 0;
-    while (wait_for_user) {
-      if (nozzle_timed_out == true)
-        lcd_filament_change_show_message(FILAMENT_CHANGE_MESSAGE_INSERT);
-      else break;
+    while (wait_for_user && nozzle_timed_out) {
       #if HAS_BUZZER
         filament_change_beep();
       #endif
       idle(true);
     }
 
-    // Show load message
+    // Show "load" message
     lcd_filament_change_show_message(FILAMENT_CHANGE_MESSAGE_LOAD);
 
-    idle();
-
     // Load filament
     if (code_seen('L')) destination[E_AXIS] -= code_value_axis_units(E_AXIS);
     #if defined(FILAMENT_CHANGE_LOAD_LENGTH) && FILAMENT_CHANGE_LOAD_LENGTH > 0
 
     lcd_filament_change_show_message(FILAMENT_CHANGE_MESSAGE_RESUME);
 
-    KEEPALIVE_STATE(IN_HANDLER);
-
     // Set extruder to saved position
     destination[E_AXIS] = current_position[E_AXIS] = lastpos[E_AXIS];
     planner.set_e_position_mm(current_position[E_AXIS]);
   millis_t ms = millis();
 
   if (max_inactive_time && ELAPSED(ms, previous_cmd_ms + max_inactive_time)) kill(PSTR(MSG_KILLED));
-	
-  #if ENABLED(FILAMENT_CHANGE_FEATURE)
-    #ifdef STEPPER_MOTORS_DONT_TIMEOUT_DURING_FILAMENT_CHANGE
-      if (busy_doing_M600 == false )	   // We only allow the stepper motors to time out if
-    #endif                                 // we are not in the middle of an M600 command.
+
+  // Prevent steppers timing-out in the middle of M600
+  #if ENABLED(FILAMENT_CHANGE_FEATURE) && ENABLED(FILAMENT_CHANGE_NO_STEPPER_TIMEOUT)
+    #define M600_TEST !busy_doing_M600
+  #else
+    #define M600_TEST true
   #endif
              
-  if (stepper_inactive_time && ELAPSED(ms, previous_cmd_ms + stepper_inactive_time)
+  if (M600_TEST && stepper_inactive_time && ELAPSED(ms, previous_cmd_ms + stepper_inactive_time)
       && !ignore_stepper_queue && !planner.blocks_queued()) {
     #if ENABLED(DISABLE_INACTIVE_X)
       disable_x();

Marlin/ultralcd.cpp

     // Change filament
     //
     #if ENABLED(FILAMENT_CHANGE_FEATURE)
-   	  if (!thermalManager.tooColdToExtrude(active_extruder))
+      if (!thermalManager.tooColdToExtrude(active_extruder))
         MENU_ITEM(function, MSG_FILAMENTCHANGE, lcd_enqueue_filament_change);
     #endif
 
     }
   #endif // LCD_INFO_MENU
 
-    /**
-     *
-     * Filament Change Feature Screens
-     *
-     */
+  /**
+   *
+   * Filament Change Feature Screens
+   *
+   */
   #if ENABLED(FILAMENT_CHANGE_FEATURE)
 
     void lcd_filament_change_toocold_menu() {
       START_MENU();
       STATIC_ITEM(MSG_HEATING_FAILED_LCD, true, true);
-      STATIC_ITEM (MSG_FILAMENT_CHANGE_MINTEMP STRINGIFY(EXTRUDE_MINTEMP) ".", false, false);
+      STATIC_ITEM(MSG_FILAMENT_CHANGE_MINTEMP STRINGIFY(EXTRUDE_MINTEMP) ".", false, false);
       MENU_BACK(MSG_BACK);
-      STATIC_ITEM (" ");
+      STATIC_ITEM(" ");
       STATIC_ITEM(MSG_FILAMENT_CHANGE_NOZZLE, false, true);
       lcd_implementation_hotend_status();
       END_MENU();
       switch (message) {
         case FILAMENT_CHANGE_MESSAGE_INIT:
           defer_return_to_status = true;
-          lcdDrawUpdate = LCDVIEW_CALL_REDRAW_NEXT;
           lcd_goto_screen(lcd_filament_change_init_message);
           break;
         case FILAMENT_CHANGE_MESSAGE_UNLOAD:
-          lcdDrawUpdate = LCDVIEW_CALL_REDRAW_NEXT;
           lcd_goto_screen(lcd_filament_change_unload_message);
           break;
         case FILAMENT_CHANGE_MESSAGE_INSERT:
-          lcdDrawUpdate = LCDVIEW_CALL_REDRAW_NEXT;
           lcd_goto_screen(lcd_filament_change_insert_message);
           break;
         case FILAMENT_CHANGE_MESSAGE_LOAD:
-          lcdDrawUpdate = LCDVIEW_CALL_REDRAW_NEXT;
           lcd_goto_screen(lcd_filament_change_load_message);
           break;
         case FILAMENT_CHANGE_MESSAGE_EXTRUDE:
-          lcdDrawUpdate = LCDVIEW_CALL_REDRAW_NEXT;
           lcd_goto_screen(lcd_filament_change_extrude_message);
           break;
         case FILAMENT_CHANGE_MESSAGE_CLICK_TO_HEAT_NOZZLE:
-          lcdDrawUpdate = LCDVIEW_CALL_REDRAW_NEXT;
           lcd_goto_screen(lcd_filament_change_heat_nozzle);
           break;
         case FILAMENT_CHANGE_MESSAGE_WAIT_FOR_NOZZLES_TO_HEAT:
-          lcdDrawUpdate = LCDVIEW_CALL_REDRAW_NEXT;
           lcd_goto_screen(lcd_filament_change_wait_for_nozzles_to_heat);
           break;
         case FILAMENT_CHANGE_MESSAGE_OPTION:

Marlin/ultralcd_impl_DOGM.h

 
 static void lcd_implementation_hotend_status() {
   u8g.setPrintPos(58, 60);
-  lcd_print( (char) '0'+active_extruder );
-  lcd_print( ' ' ); 
-  lcd_print( ' ' ); 
+  lcd_print((char)('0' + active_extruder));
+  lcd_print(' ');
+  lcd_print(' ');
   lcd_print(itostr3(thermalManager.degHotend(active_extruder)));
   lcd_print('/');
   lcd_print(itostr3(thermalManager.degTargetHotend(active_extruder)));

Marlin/ultralcd_impl_HD44780.h

 #endif // LCD_PROGRESS_BAR
 
 static void lcd_implementation_hotend_status() {
-  lcd.setCursor(10,3);
+  lcd.setCursor(10, 3);
   lcd.print(LCD_STR_THERMOMETER[active_extruder]);
   lcd.print(itostr3(thermalManager.degHotend(active_extruder)));
   lcd.print('/');