Below is the API for the OCaml standard library. It's directly copied over from the OCaml Manual, formatted to the Reason syntax and styled accordingly. The API docs are work-in-progress; we'll be polishing these gradually!
If you're targeting JavaScript, the API docs for BuckleScript includes all of below, plus JS-specific APIs.
module Stack: sig .. end
   This module implements stacks (LIFOs), with in-place modification.
type 'a t 
'a.exception Empty
val create : unit -> 'a t
val push : 'a -> 'a t -> unit
push x s adds the element x at the top of stack s.val pop : 'a t -> 'a
pop s removes and returns the topmost element in stack s,
   or raises Empty if the stack is empty.val top : 'a t -> 'a
top s returns the topmost element in stack s,
   or raises Empty if the stack is empty.val clear : 'a t -> unit
val copy : 'a t -> 'a t
val is_empty : 'a t -> bool
true if the given stack is empty, false otherwise.val length : 'a t -> int
val iter : ('a -> unit) -> 'a t -> unititer f s applies f in turn to all elements of s,
   from the element at the top of the stack to the element at the
   bottom of the stack. The stack itself is unchanged.