package frama-c

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package frama-c
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include module type of Result

Results

type ('a, 'e) t = ('a, 'e) result =
  1. | Ok of 'a
  2. | Error of 'e

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

val ok : 'a -> ('a, 'e) result

ok v is Ok v.

val error : 'e -> ('a, 'e) result

error e is Error e.

val value : ('a, 'e) result -> default:'a -> 'a

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

val get_ok : ('a, 'e) result -> 'a

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

val get_error : ('a, 'e) result -> 'e

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

val bind : ('a, 'e) result -> ('a -> ('b, 'e) result) -> ('b, 'e) result

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

val join : (('a, 'e) result, 'e) result -> ('a, 'e) result

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

val map : ('a -> 'b) -> ('a, 'e) result -> ('b, 'e) result

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 -> ('a, 'f) result

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

val fold : ok:('a -> 'c) -> error:('e -> 'c) -> ('a, 'e) result -> '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 -> unit

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

val iter_error : ('e -> unit) -> ('a, 'e) result -> unit

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

Predicates and comparisons

val is_ok : ('a, 'e) result -> bool

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

val is_error : ('a, 'e) result -> 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 -> ('a, 'e) result -> bool

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

val compare : ok:('a -> 'a -> int) -> error:('e -> 'e -> int) -> ('a, 'e) result -> ('a, 'e) result -> int

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

Converting

val to_option : ('a, 'e) result -> 'a option

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

val to_list : ('a, 'e) result -> 'a list

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

val to_seq : ('a, 'e) result -> 'a Seq.t

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

val zip : ('a, 'e) result -> ('b, 'e) result -> ('a * 'b, 'e) result

zip r1 r2 regroups values in a pair Ok (v1, v2) if both arguments are Ok v1 and Ok v2 and propagate errors in other cases. If both r1 and r2 are errors we keep the first one, in this case r1.

module Operators : sig ... end
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