Coding style.

- The fill3.context can create the screen update task.

eris/__main__.py

@@ -1139,14 +1139,9 @@ def main(root_path, loop, worker_count=None, editor_command=None, theme=None,
         for worker in screen.workers:
             loop.create_task(worker.future)
         if sys.stdout.isatty():
-            update_task = loop.create_task(
-                fill3.update_screen(screen, appearance_changed_event))
-            try:
             with fill3.context(loop, appearance_changed_event, screen,
                                exit_loop=exit_loop):
                 loop.run_forever()
-            finally:
-                update_task.cancel()
             log.log_message("Program stopped.")
         else:
             try:

eris/fill3.py

@@ -499,11 +499,16 @@ def context(loop, appearance_changed_event, screen_widget, exit_loop=None):
          signal_handler(loop, signal.SIGTERM, exit_loop), \
          terminal.alternate_buffer(), terminal.interactive(), \
          terminal.mouse_tracking():
+        update_task = loop.create_task(
+            update_screen(screen_widget, appearance_changed_event))
+        try:
             loop.add_reader(sys.stdin, on_terminal_input, screen_widget)
             try:
                 yield
             finally:
                 loop.remove_reader(sys.stdin)
+        finally:
+            update_task.cancel()
 
 
 ##########################
@@ -535,13 +540,8 @@ def _main():
     loop = asyncio.get_event_loop()
     appearance_changed_event = asyncio.Event()
     screen = _Screen(appearance_changed_event)
-    update_task = loop.create_task(
-        update_screen(screen, appearance_changed_event))
-    try:
     with context(loop, appearance_changed_event, screen):
         loop.run_forever()
-    finally:
-        update_task.cancel()
 
 
 if __name__ == "__main__":