Ok, found this https://discourse.elm-lang.org/t/can-phantom-types-be-used-to-restrict-the-possible-transitions-in-a-state-machine/508/8
Very interesting and there is a state machine package. What searching can give you! 
Ok, found this https://discourse.elm-lang.org/t/can-phantom-types-be-used-to-restrict-the-possible-transitions-in-a-state-machine/508/8
Very interesting and there is a state machine package. What searching can give you!