module type PETRI_TYPES = sig

  type node
  type place
  type token
  val node_id : node -> int
end

module Petri_net =
  functor (PTypes  : PETRI_TYPES) ->
struct
  type node = PTypes.node
  type place = PTypes.place
  type token = PTypes.token

  type transition = ( node list * place * node list)


  class petri_net (places_i ) (nodes_i ) (transitions_i ) =
  object

    val places = places_i
    val nodes = nodes_i
    val transitions = transitions_i

    val places_number = Array.length places_i

    method check_init =
      let rec check_transition t =
      (* si on faisait du coq, ce serait encore plus beau *)
        match t with
        | h :: t, l2 ->
           PTypes.node_id h >= 0 && PTypes.node_id h < places_number && check_transition (t,l2)
        | [], h :: t ->
           PTypes.node_id h >= 0 && PTypes.node_id h < places_number && check_transition ([],t)
        | _ -> true

      and check_transitions t_list =
        match t_list with
        | [] -> true
        | t :: t_list' ->
           check_transition t && check_transitions t_list'
      in
      check_transitions transitions


  end
end;;