I would like to know if it's still possible to create such a machine with pytransition.
The way HSMs are created and managed has changed in 0.8 but you can of course use (deeply) nested states. For a state to have substates, you need to pass the states (or children) parameter with the state definitions/objects you'd like to nest. Furthermore, you can pass transitions for that particular scope. I am using HierarchicalGraphMachine since this allows me to create a graph right away.
from transitions.extensions.factory import HierarchicalGraphMachine
states = [
# create a state named A
{"name": "A",
# with the following children
"states":
# a state named '1' which will be accessible as 'A_1'
["1", {
# and a state '2' with its own children ...
"name": "2",
# ... 'a' and 'b'
"states": ["a", "b"],
"transitions": [["go", "a", "b"],["go", "b", "a"]],
# when '2' is entered, 'a' should be entered automatically.
"initial": "a"
}],
# we could also pass [["go", "A_1", "A_2"]] to the machine constructor
"transitions": [["go", "1", "2"]],
"initial": "1"
}]
m = HierarchicalGraphMachine(states=states, initial="A")
m.go()
m.get_graph().draw("foo.png", prog="dot") # [1]
Output of 1:
