module Lazy = struct ... end
Deferred computations.
type 'a status =
| Delayed of (unit -> 'a) |
| Value of 'a |
| Exception of exn |
type 'a t = 'a status Pervasives.ref
A value of type 'a Lazy.t is a deferred computation (also called a
suspension) that computes a result of type 'a. The expression
lazy (expr) returns a suspension that computes expr. *
exception Undefined
val force : 'a t -> 'a
Lazy.force x computes the suspension x and returns its result.
If the suspension was already computed, Lazy.force x returns the
same value again. If it raised an exception, the same exception is
raised again.
Raise Undefined if the evaluation of the suspension requires its
own result.