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Module type State.Local

module type Local = sig .. end

Operations on the local state required for registering a new state via State_builder.Register. The local state is the mutable value which you would like to be project-compliant.

type t

Type of the state to register.

val create : unit -> t

How to create a new fresh state which must be equal to the initial state: that is, if you never change the state, create () and get
      () must be equal (see invariant 1 below).

val clear : t -> unit

How to clear a state. After clearing, the state should be observationally the same that after its creation (see invariant 2 below).

val get : unit -> t

How to access to the current state. Be aware of invariants 3 and 4 below.

val set : t -> unit

How to change the current state. Be aware of invariants 3 and 4 below.

The four following invariants must hold.

  1. create () returns a fresh value
  2. forall (p:t) copy p returns a fresh value
  3. forall (p:t), create () = (clear p; set p; get ())
  4. forall (p1:t),(p2:t) such that p1 != p2, (set p1; get ()) != s2
val clear_some_projects : (Project_skeleton.t -> bool) -> t -> bool

clear_if_project f x must clear any value v of type project of x such that f v is true. Of course, if the type t does not contain any object of type project, this function should do nothing and safely returns fun _ -> false.