Accessing events in behaviors and guards
There are two possibilities to get the actual event types in behaviors and/or guards. One is by using the predefined macros and one is by manually casting the events to the actual event type.
Strongly typed events (C++11 only)
In yasmine there are two very useful macros for passing handlers as behaviors into a state or a transition:
|
Macro |
Syntax |
Description |
|
Y_BEHAVIOR_METHOD2 |
Y_BEHAVIOR_METHOD2( _class_instance, _method1[, _method2, _method3, _method4, _method5, _method6, _method7, _method8, _method9, _method10] ) |
The macro adds the specified class method(s) as behavior(s) to states or transitions. |
|
Y_BEHAVIOR_FUNCTION2 |
Y_BEHAVIOR_FUNCTION2( _function1[, _function2, _function3, _function4, _function5, _function6, _function7, _function8, _function9, _function10] ) |
The macro adds the specified function(s) as behavior(s) to states or transitions. |
|
Y_GUARD_METHOD2 |
Y_GUARD_METHOD2( _class_instance, _method1[, _method2, _method3, _method4, _method5, _method6, _method7, _method8, _method9, _method10] ) |
The macro adds the specified class method(s) as guard(s) to states or transitions. |
|
Y_GUARD_FUNCTION2 |
Y_GUARD_FUNCTION2( _function1[, _function2, _function3, _function4, _function5, _function6, _function7, _function8, _function9, _function10] ) |
The macro adds the specified function(s) as guard(s) to states or transitions. |
Passing the handlers correctly
There are some things you have to pay attention to when passing handlers to the state machine:
You have to make sure to pass a handler for each and every event type that can reach a state (or that can trigger a transition) to Y_BEHAVIOR_METHOD2, Y_BEHAVIOR_FUNCTION2, Y_GUARD_METHOD2 or Y_GUARD_FUNCTION2! If you fail to do this, the state machine will abort, if such an event occurs.
These macros are only available with C++11 support. Inside the Events with parameters example some use cases of this macros are shown.
If you need macros for events with more than 5 parameters, you can just create your own macros by copying the predefined ones and extending them with more parameters.
Manual cast
It is possible to use a dynamic_cast to adjust the event type to its actual type inside a behavior:
const sxy::event_2* event_with_param = dynamic_cast< const sxy::event_2* >( &_event );The complete code can be found in the Events with parameters example.