package b0
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doc/b0.std/B0_std/Result/index.html
Module B0_std.Result
Result values (as in 4.08)
Except for the function of this section that's the Result module that went into 4.08.
Results
The type for result values. Either a value Ok v or an error Error e.
val ok : 'a -> ('a, 'e) resultok v is Ok v.
val error : 'e -> ('a, 'e) resulterror e is Error e.
val value : ('a, 'e) result -> default:'a -> 'avalue r ~default is v if r is Ok v and default otherwise.
val get_ok : ('a, 'e) result -> 'aget_ok r is v if r is Ok v and
val get_error : ('a, 'e) result -> 'eget_error r is e if r is Error e and
bind r f is Ok (f v) if r is Ok v and r if r is Error _.
join rr is r if rr is Ok r and rr if rr is Error _.
map f r is Ok (f v) if r is Ok v and r if r is Error _.
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 -> 'cfold ~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 -> unititer f r is f v if r is Ok v and () otherwise.
val iter_error : ('e -> unit) -> ('a, 'e) result -> unititer_error f r is f e if r is Error e and () otherwise.
Predicates and comparisons
val is_ok : ('a, 'e) result -> boolis_ok r is true iff r is Ok _.
val is_error : ('a, 'e) result -> boolis_error r is true iff r is Error _.
val equal :
ok:('a -> 'a -> bool) ->
error:('e -> 'e -> bool) ->
('a, 'e) result ->
('a, 'e) result ->
boolequal ~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 ->
intcompare ~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.
Interacting with Stdlib exceptions
val to_failure : ('a, string) result -> 'ato_failure r is failwith e if r is Error e and v if r is Ok v.
val catch_failure : (unit -> 'a) -> ('a, string) resultcatch_failure f is try Ok (f ()) with Failure e -> Error e
val catch_sys_error : (unit -> 'a) -> ('a, string) resultcatch_sys_error f is try Ok (f ()) with Sys_error e -> Error e
Converting
val to_option : ('a, 'e) result -> 'a optionto_option r is r as an option, mapping Ok v to Some v and Error _ to None.
val to_list : ('a, 'e) result -> 'a listto_list r is [v] if r is Ok v and [] otherwise.