Reason · Reason lets you write simple, fast and quality type safe code while leveraging both the JavaScript & OCaml ecosystems.

sig
 type 'a t = 'a CamlinternalLazy.t
 exception Undefined
 external force : 'a Lazy.t -> 'a = "%lazy_force"
 val map : ('a -> 'b) -> 'a Lazy.t -> 'b Lazy.t
 val is_val : 'a Lazy.t -> bool
 val from_val : 'a -> 'a Lazy.t
 val map_val : ('a -> 'b) -> 'a Lazy.t -> 'b Lazy.t
 val from_fun : (unit -> 'a) -> 'a Lazy.t
 val force_val : 'a Lazy.t -> 'a
end