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type 'a t = 'a option =
| None
| Some of 'a
module O = struct
let (>>|) t f =
match t with
| None -> None
| Some a -> Some (f a)
let (>>=) t f =
match t with
| None -> None
| Some a -> f a
end
let map t ~f = O.(>>|) t f
let bind t ~f = O.(>>=) t f
let iter t ~f =
match t with
| None -> ()
| Some x -> f x
let value t ~default =
match t with
| Some x -> x
| None -> default
let value_exn = function
| Some x -> x
| None -> invalid_arg "Option.value_exn"
let some x = Some x
let some_if cond x =
if cond then Some x else None
let is_some = function
| None -> false
| Some _ -> true
let is_none = function
| None -> true
| Some _ -> false
let both x y =
match x, y with
| Some x, Some y -> Some (x, y)
| _ -> None
let to_list = function
| None -> []
| Some x -> [x]
let equal eq x y =
match (x, y) with
| None, None -> true
| Some _, None -> false
| None, Some _ -> false
| Some sx, Some sy -> eq sx sy
let compare cmp x y =
match x, y with
| None, None -> Ordering.Eq
| Some _, None -> Gt
| None, Some _ -> Lt
| Some x, Some y -> cmp x y