package b0

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Software construction and deployment kit

Install 

dune-project
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erratique.ch Readme Changelog ISC; BSD-2-Clause License Edit opam file Versions (2)

Authors

  1. T
    The b0 programmers

Maintainers

  1. Daniel Bünzli

Sources

b0-0.0.6.tbz
sha512=e9aa779e66c08fc763019f16d4706f465d16c05d6400b58fbd0313317ef33ddea51952e2b058db28e65f7ddb7012f328c8bf02d8f1da17bb543348541a2587f0

doc/b0.std/B0_std/Result/index.html

Module B0_std.ResultSource

Result values.

All additions available in OCaml 5.4

include module type of Result

Results

Sourcetype ('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.

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

ok v is Ok v.

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

error e is Error e.

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

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

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

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

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

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

Sourceval 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 _.

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

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

Sourceval 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 _.

Sourceval 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 _.

Sourceval 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.

Sourceval iter : ('a -> unit) -> ('a, 'e) result -> unit

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

Sourceval 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

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

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

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

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

Sourceval 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 _.

Sourceval 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

Sourceval 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.

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

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

Sourceval 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.

Extracting results

Sourceval get_ok' : ('a, string) result -> 'a

get_ok' r is like get_ok but the message of Invalid_argument is the error meesage.

Sourceval error_to_failure : ('a, string) result -> 'a

error_to_failure r is failwith e if r is Error e and v if r is Ok v.

Sourceval retract : ('a, 'a) result -> 'a

retract r is v if r is Ok v or Error v.

Let operators

Sourcemodule Syntax : sig ... end

let operators.