tuxemon.event.eventaction module

class tuxemon.event.eventaction.EventAction[source]

Bases: ABC

EventActions are executed during gameplay.

EventAction subclasses implement “actions” defined in Tuxemon maps. All subclasses, at minimum, must implement the following:

  • The EventAction.start() method

  • A meaningful name, which must match the name in map file actions

By populating the “valid_parameters” class attribute, subclasses will be assigned a “parameters” instance attribute that holds the parameters passed to the action in the map file. It is also used to check the syntax of actions, by verifying the correct type and number of parameters passed.

If an EventAction does not implement the update method, it will only run for one frame. If it does implement the update method, then it will continue to run until it is stopped, or the EventEngine is stopped.

If you wish to stop an EventAction, call the stop method. Calling stop() signals to the EventEngine that this EventAction is done, and can be removed from the processing loop at the end of the frame.

Update will be called every frame the EventAction is running, including the first frame it is started. You should eventually stop the action during update.

The EventAction class supports the context protocol, and you may also use them outside of the EventEngine, but can only be run in a blocking manner. Do not execute EventActions outside the Engine if the action will block forever, as it will freeze the game.


** this is a work-in-progress feature, that may change in time **

Tuxemon supports type-checking of the parameters defined in the maps.

valid_parameters may be the following format (may change):

(type, name)

  • the type may be any valid python type, or even a python class or function

  • type may be a single type, or a tuple of types

  • type, if a tuple, may include None to indicate the parameter is optional

  • name must be a valid python string

After parsing the parameters of the MapAction, the parameter’s value will be passed to the type constructor.

Example types: str, int, float, Monster, Item

(int, “duration”) => duration must be an int ((int, float), “duration”) => can be an int or float ((int, float, None), “duration”) => is optional

(Monster, “monster_slug”) => a Monster instance will be created

  • session – Object containing the session information.

  • parameters – Parameters of the action.


Called only once, when action is stopped and needs to close.

You do not need to override this, but it may be useful for some actions which require special handling before they are closed.

Return type:


property done: bool

Will be true when action is finished.

If you need the action to stop, call EventAction.stop().


Blocking call to run the action. Will setup and cleanup action.

This may cause the game to hang if an action is waiting on game changes.

Return type:


name: ClassVar[str]

Blocking call to run the action, without start or cleanup.

It is better to use EventAction.execute().

This may cause the game to hang if an action is waiting on game changes.

Return type:


session: Session
abstract start()[source]

Called only once, when the action is started.

For all actions, you will need to override this method.

For actions that only need to run one frame you can simply put all the code here. If the action will need to run over several frames, you can init your action here, then override the update method.

Return type:



Call when the action is done.

EventAction will be removed at end of frame.

If an EventAction overrides update, it must eventually call this method.

Return type:



Called once per frame while action is running.

It is also called on the first frame when EventAction is started.

If you do not override this, then the action will stop after it is started, and live for only one frame.

If you do override this, then this method will be run every frame until EventAction.stop() is called. If you do not ever call stop(), then this action will block all others in the list and will continue to run until the parent EventEngine is stopped.

Return type: