I think interfaces in Julia might go something like

    interface AnimalActions
        function walk(x::Animal) end
        function call(x::Animal, y::Animal) end
        function eat(x::Animal, z::Food) end
    end
    
    struct Dog <: Animal
        name::String
    end
    
    AnimalActions.walk(x::Dog) = true
    AnimalActions.call(x::Dog, y::Animal) = true
    AnimalActions.eat(x::Dog, z::Food) = true
    
    setinterface Dog AnimalActions end

and then I guess using it like

    using AnimalActions
    d = Dog("rufus")
    walk(d)