package b0

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Software construction and deployment kit

Install 

dune-project
 Dependency

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

product r0 r1 is Ok (v0, v1) if r0 is Ok v0 and r1 is Ok v2 and otherwise returns the error of r0, if any, or the error of r1.

  • since 5.4
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.

Syntax

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.