Module State

module State: sig .. end
Definition of checks states.

type id 
The type of state identifiers.
type 'a getter = id -> 'a 
The type of function used for retrieving a state from an identifier.
type 'a setter = id -> 'a -> unit 
The type of function used for setting a state from an identifier.
val next_id : unit -> id
Returns a new state identifier.
val init : (unit -> 'a) -> 'a getter * 'a setter
init f Initializes a (collection of) state(s) by returning a pair that consist of a getter and setter. The function f will be used to create an initial value for the state; it will be called upon the first try to retrieve an element, if it has not been set before.