module Option: CCOpt
type 'a
t = 'a option
val map : ('a -> 'b) -> 'a t -> 'b t
Transform the element inside, if any
val map_or : default:'b -> ('a -> 'b) -> 'a t -> 'b
map_or ~default f o
is f x
if o = Some x
, default
otherwise
Since 0.16
val map_lazy : (unit -> 'b) -> ('a -> 'b) -> 'a t -> 'b
map_lazy default_fn f o
if f o
if o = Some x
, default_fn ()
otherwise
Since 1.2
val is_some : 'a t -> bool
val is_none : 'a t -> bool
Since 0.11
val compare : ('a -> 'a -> int) -> 'a t -> 'a t -> int
val equal : ('a -> 'a -> bool) -> 'a t -> 'a t -> bool
val return : 'a -> 'a t
Monadic return, that is return x = Some x
val (>|=) : 'a t -> ('a -> 'b) -> 'b t
val (>>=) : 'a t -> ('a -> 'b t) -> 'b t
Monadic bind
val flat_map : ('a -> 'b t) -> 'a t -> 'b t
Flip version of >>=
val map2 : ('a -> 'b -> 'c) -> 'a t -> 'b t -> 'c t
val iter : ('a -> unit) -> 'a t -> unit
Iterate on 0 or 1 element
val fold : ('a -> 'b -> 'a) -> 'a -> 'b t -> 'a
Fold on 0 or 1 element
val filter : ('a -> bool) -> 'a t -> 'a t
Filter on 0 or 1 element
Since 0.5
val if_ : ('a -> bool) -> 'a -> 'a option
if_ f x
is Some x
if f x
, None
otherwise
Since 0.17
val exists : ('a -> bool) -> 'a t -> bool
Since 0.17
val for_all : ('a -> bool) -> 'a t -> bool
Since 0.17
val get_or : default:'a -> 'a t -> 'a
get_or ~default o
extracts the value from o
, or
returns default
if o = None
.
Since 0.18
val get_exn : 'a t -> 'a
Open the option, possibly failing if it is None
Raises Invalid_argument
if the option is None
val get_lazy : (unit -> 'a) -> 'a t -> 'a
get_lazy default_fn x
unwraps x
, but if x = None
it returns default_fn ()
instead.
Since 0.6.1
val sequence_l : 'a t list -> 'a list t
sequence_l [x1; x2; ...; xn]
returns Some [y1;y2;...;yn]
if
every xi
is Some yi
. Otherwise, if the list contains at least
one None
, the result is None
.
val wrap : ?handler:(exn -> bool) -> ('a -> 'b) -> 'a -> 'b option
wrap f x
calls f x
and returns Some y
if f x = y
. If f x
raises
any exception, the result is None
. This can be useful to wrap functions
such as Map.S.find
.
handler
: the exception handler, which returns true
if the
exception is to be caught.
val wrap2 : ?handler:(exn -> bool) -> ('a -> 'b -> 'c) -> 'a -> 'b -> 'c option
wrap2 f x y
is similar to wrap1
but for binary functions.
Applicative
val pure : 'a -> 'a t
val (<*>) : ('a -> 'b) t -> 'a t -> 'b t
val (<$>) : ('a -> 'b) -> 'a t -> 'b t
Alternatives
val or_ : else_:'a t -> 'a t -> 'a t
or_ ~else_ a
is a
if a
is Some _
, else_
otherwise
Since 1.2
val or_lazy : else_:(unit -> 'a t) -> 'a t -> 'a t
or_lazy else_ a
is a
if a
is Some _
, else_ ()
otherwise
Since 1.2
val (<+>) : 'a t -> 'a t -> 'a t
a <+> b
is a
if a
is Some _
, b
otherwise
val choice : 'a t list -> 'a t
choice
returns the first non-None
element of the list, or None
Infix Operators
module Infix: sig
.. end
Conversion and IO
val to_list : 'a t -> 'a list
val of_list : 'a list -> 'a t
Head of list, or None
val to_result : 'e -> 'a t -> ('a, 'e) Result.result
Since 1.2
val to_result_lazy : (unit -> 'e) -> 'a t -> ('a, 'e) Result.result
Since 1.2
val of_result : ('a, 'b) Result.result -> 'a t
Since 1.2
type 'a
sequence = ('a -> unit) -> unit
type 'a
gen = unit -> 'a option
type 'a
printer = Format.formatter -> 'a -> unit
type 'a
random_gen = Random.State.t -> 'a
val random : 'a random_gen -> 'a t random_gen
val choice_seq : 'a t sequence -> 'a t
choice_seq s
is similar to
CCOpt.choice
, but works on sequences.
It returns the first
Some x
occurring in
s
, or
None
otherwise.
Since 0.13
val to_gen : 'a t -> 'a gen
val to_seq : 'a t -> 'a sequence
val pp : 'a printer -> 'a t printer