Call triggers by name

[juan11iguel]

Call triggers by name

[aleneum]

Hi @juan11iguel,

It would be nice if there was a convenience method to call triggers by its name (a string).

good news: you can do that via the decorated trigger method. In the README Non-quickstart right before the next section:

Furthermore, there is a method called trigger now attached to your model (if it hasn't been there before). This method lets you execute transitions by name in case dynamic triggering is required.

Or in the section about Callback Execution Order:

In summary, there are currently three ways to trigger events. You can call a model's convenience functions like lump.melt(), execute triggers by name such as lump.trigger("melt") or dispatch events on multiple models with machine.dispatch("melt")

Long story short: That's how it's done:

from transitions import Machine

states = ['solid', 'liquid', 'gas', 'plasma']

transitions = [
    {'trigger': 'melt', 'source': 'solid', 'dest': 'liquid'},
    {'trigger': 'evaporate', 'source': 'liquid', 'dest': 'gas'},
    {'trigger': 'sublimate', 'source': 'solid', 'dest': 'gas'},
    {'trigger': 'ionize', 'source': 'gas', 'dest': 'plasma'}
]

machine = Machine(states=states, transitions=transitions, initial='liquid')
machine.trigger("evaporate")
assert machine.is_gas()

Note that I did not pass lump as an argument. The first argument passed to Machine acts as a model. So when I pass something there, all the convenience functions will be added to the object. If no model is provided machine itself acts as a model.

Let me know if this covers your use case and best regards.

[juan11iguel]

Ha! It seems I cannot read, thanks for the detailed response, this solves it then.

Best regards