OCaml library : Stdlib.Result (original) (raw)

Module Stdlib.Result

module Result: [Result](Result.html)

Results

type ('a, 'e) t = ('a, 'e) [result](Stdlib.html#TYPEresult) =

The type for result values. Either a value Ok v or an error Error e.

val ok : 'a -> ('a, 'e) [result](Stdlib.html#TYPEresult)

val error : 'e -> ('a, 'e) [result](Stdlib.html#TYPEresult)

val value : ('a, 'e) [result](Stdlib.html#TYPEresult) -> default:'a -> 'a

value r ~default is v if r is Ok v and default otherwise.

val get_ok : ('a, 'e) [result](Stdlib.html#TYPEresult) -> 'a

get_ok r is v if r is Ok v and raise otherwise.

• Raises Invalid_argument if r is Error _.

val get_error : ('a, 'e) [result](Stdlib.html#TYPEresult) -> 'e

get_error r is e if r is Error e and raise otherwise.

• Raises Invalid_argument if r is Ok _.

val bind : ('a, 'e) [result](Stdlib.html#TYPEresult) -> ('a -> ('b, 'e) [result](Stdlib.html#TYPEresult)) -> ('b, 'e) [result](Stdlib.html#TYPEresult)

bind r f is f v if r is Ok v and r if r is Error _.

val join : (('a, 'e) [result](Stdlib.html#TYPEresult), 'e) [result](Stdlib.html#TYPEresult) -> ('a, 'e) [result](Stdlib.html#TYPEresult)

join rr is r if rr is Ok r and rr if rr is Error _.

val map : ('a -> 'b) -> ('a, 'e) [result](Stdlib.html#TYPEresult) -> ('b, 'e) [result](Stdlib.html#TYPEresult)

map f r is Ok (f v) if r is Ok v and r if r is Error _.

val map_error : ('e -> 'f) -> ('a, 'e) [result](Stdlib.html#TYPEresult) -> ('a, 'f) [result](Stdlib.html#TYPEresult)

map_error f r is Error (f e) if r is Error e and r ifr is Ok _.

val fold : ok:('a -> 'c) -> error:('e -> 'c) -> ('a, 'e) [result](Stdlib.html#TYPEresult) -> 'c

fold ~ok ~error r is ok v if r is Ok v and error e if r is Error e.

val iter : ('a -> unit) -> ('a, 'e) [result](Stdlib.html#TYPEresult) -> unit

iter f r is f v if r is Ok v and () otherwise.

val iter_error : ('e -> unit) -> ('a, 'e) [result](Stdlib.html#TYPEresult) -> unit

iter_error f r is f e if r is Error e and () otherwise.

Predicates and comparisons

val is_ok : ('a, 'e) [result](Stdlib.html#TYPEresult) -> bool

is_ok r is true if and only if r is Ok _.

val is_error : ('a, 'e) [result](Stdlib.html#TYPEresult) -> bool

is_error r is true if and only if r is Error _.

val equal : ok:('a -> 'a -> bool) -> error:('e -> 'e -> bool) -> ('a, 'e) [result](Stdlib.html#TYPEresult) -> ('a, 'e) [result](Stdlib.html#TYPEresult) -> bool

equal ~ok ~error r0 r1 tests equality of r0 and r1 using ok and error to respectively compare values wrapped by Ok _ andError _.

val compare : ok:('a -> 'a -> int) -> error:('e -> 'e -> int) -> ('a, 'e) [result](Stdlib.html#TYPEresult) -> ('a, 'e) [result](Stdlib.html#TYPEresult) -> int

compare ~ok ~error r0 r1 totally orders r0 and r1 using ok anderror to respectively compare values wrapped by Ok _ and Error _.Ok _ values are smaller than Error _ values.

Converting

val to_option : ('a, 'e) [result](Stdlib.html#TYPEresult) -> 'a option

to_option r is r as an option, mapping Ok v to Some v andError _ to None.

val to_list : ('a, 'e) [result](Stdlib.html#TYPEresult) -> 'a list

to_list r is [v] if r is Ok v and [] otherwise.

val to_seq : ('a, 'e) [result](Stdlib.html#TYPEresult) -> 'a [Seq.t](Seq.html#TYPEt)

to_seq r is r as a sequence. Ok v is the singleton sequence containing v and Error _ is the empty sequence.