@spec allowed([t()], from: state(), to: state(), with: event()) :: [
  {state(), state(), event()}
]

Returns the list of all the transitions, matching the options.

Used internally for the validations.

iex> {:ok, transitions} =
...>   Finitomata.Mermaid.parse(
...>     "idle --> |to_s1| s1\n" <>
...>     "s1 --> |to_s2| s2\n" <>
...>     "s1 --> |to_s3| s3\n" <>
...>     "s2 --> |to_s3| s3")
...> Finitomata.Transition.allowed(transitions, to: [:idle, :*])
[{:*, :idle, :__start__}, {:s3, :*, :__end__}]
iex> Finitomata.Transition.allowed(transitions, from: :s1)
[{:s1, :s2, :to_s2}, {:s1, :s3, :to_s3}]
iex> Finitomata.Transition.allowed(transitions, from: :s1, to: :s3)
[{:s1, :s3, :to_s3}]
iex> Finitomata.Transition.allowed(transitions, from: :s1, with: :to_s3)
[{:s1, :s3, :to_s3}]
iex> Finitomata.Transition.allowed(transitions, from: :s2, with: :to_s2)
[]

@spec allowed([t()], state(), event()) :: [state()]

Returns the list of all the transitions, matching the from state and the event.

Used internally for the validations.

iex> {:ok, transitions} =
...>   Finitomata.PlantUML.parse("[*] --> s1 : foo\ns1 --> s2 : ok\ns2 --> [*] : ko")
...> Finitomata.Transition.allowed(transitions, :s1, :foo)
[:s2]
...> Finitomata.Transition.allowed(transitions, :s1, :*)
[]

@spec allowed?([t()], state(), state()) :: boolean()

Returns true if the transition from → to is allowed, false otherwise.

iex> {:ok, transitions} =
...>   Finitomata.PlantUML.parse("[*] --> s1 : foo\ns1 --> s2 : ok\ns2 --> [*] : ko")
...> Finitomata.Transition.allowed?(transitions, :s1, :s2)
true
...> Finitomata.Transition.allowed?(transitions, :s1, :*)
false

@spec determined([t()]) :: [{state(), {event(), state()}}]

Returns Finitomata.Transition.event() if there is a determined transition from the current state.

The transition is determined, if it is the only transition allowed from the state.

Used internally for the validations.

iex> {:ok, transitions} =
...>   Finitomata.Mermaid.parse(
...>     "idle --> |to_s1| s1\n" <>
...>     "s1 --> |to_s2| s2\n" <>
...>     "s1 --> |to_s3| s3\n" <>
...>     "s2 --> |determined| s3\n" <>
...>     "s2 --> |determined| s4")
...> Finitomata.Transition.determined(transitions)
[s4: :__end__, s3: :__end__, s2: :determined, idle: :to_s1]

@spec determined([t()], state()) :: {:ok, {event(), state()}} | :error

Returns {:ok, {event(), state()}} tuple if there is a determined transition from the current state, :error otherwise.

The transition is determined, if it is the only transition allowed from the state.

Used internally for the validations.

iex> {:ok, transitions} =
...>   Finitomata.Mermaid.parse(
...>     "idle --> |to_s1| s1\n" <>
...>     "s1 --> |to_s2| s2\n" <>
...>     "s1 --> |to_s3| s3\n" <>
...>     "s2 --> |to_s3| s3")
...> Finitomata.Transition.determined(transitions, :s1)
:error
iex> Finitomata.Transition.determined(transitions, :s2)
{:ok, {:to_s3, :s3}}
iex> Finitomata.Transition.determined(transitions, :s3)
{:ok, {:__end__, :*}}

@spec entry([t()]) :: state()

Returns the state after starting one, so-called entry state.

iex> {:ok, transitions} =
...>   Finitomata.PlantUML.parse("[*] --> s1 : foo\ns1 --> s2 : ok\ns2 --> [*] : ko")
...> Finitomata.Transition.entry(transitions)
:s1

@spec responds?([t()], state(), event()) :: boolean()

Returns true if the state from hsa an outgoing transition with event, false otherwise.

iex> {:ok, transitions} =
...>   Finitomata.PlantUML.parse("[*] --> s1 : foo\ns1 --> s2 : ok\ns2 --> [*] : ko")
...> Finitomata.Transition.responds?(transitions, :s1, :ok)
true
...> Finitomata.Transition.responds?(transitions, :s1, :ko)
false

@spec states([t()]) :: [state()]

Returns the not ordered list of states, excluding the starting and ending states :*.

iex> {:ok, transitions} =
...>   Finitomata.PlantUML.parse("[*] --> s1 : foo\ns1 --> s2 : ok\ns2 --> [*] : ko")
...> Finitomata.Transition.states(transitions)
[:s1, :s2]