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in-package search v0.1.0
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travesty
-
-
travesty_containers
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-
travesty_core_kernel_exts
Library
Module
Module type
Parameter
Class
Class type
With_errors
is shorthand for On_monad (Or_error)
.
include Travesty.Traversable.Generic_on_monad
with type 'a t := 'a t
and type 'a elt := 'a
with module M := Base.Or_error
include Travesty.Traversable.Basic_generic_on_monad
with type 'a t := 'a t
with type 'a elt := 'a
with module M := Base.Or_error
Generic
refers to the container type as 'a t
, and the element type as 'a elt
; substitute t
/elt
(arity-0) or 'a t
/'a
(arity-1) accordingly below.
include Travesty.Types_intf.Generic
with type 'a t := 'a t
with type 'a elt := 'a
val map_m : 'a t -> f:('a -> 'b Base.Or_error.t) -> 'b t Base.Or_error.t
map_m c ~f
maps f
over every t
in c
, threading through monadic state.
Example:
(* Travesty_base_exts.List adds monadic traversals to a list;
With_errors (in S1_container) implements them on the On_error
monad. *)
let f x =
Or_error.(if 0 < x then error_string "negative!" else ok x)
in
List.With_errors.map_m integers ~f
val fold_map_m :
'a t ->
f:('acc -> 'a -> ('acc * 'b) Base.Or_error.t) ->
init:'acc ->
('acc * 'b t) Base.Or_error.t
fold_map_m c ~f ~init
folds f
monadically over every t
in c
, threading through an accumulator with initial value init
.
val fold_m :
'a t ->
init:'acc ->
f:('acc -> 'a -> 'acc Base.Or_error.t) ->
'acc Base.Or_error.t
fold_m x ~init ~f
folds the monadic computation f
over x
, starting with initial value init
, and returning the final value inside the monadic effect.
val iter_m :
'a t ->
f:('a -> Base.unit Base.Or_error.t) ->
Base.unit Base.Or_error.t
iter_m x ~f
iterates the monadic computation f
over x
, returning the final monadic effect.
val mapi_m :
f:(Base.int -> 'a -> 'b Base.Or_error.t) ->
'a t ->
'b t Base.Or_error.t
mapi_m ~f x
behaves as mapM
, but also supplies f
with the index of the element. This index should match the actual position of the element in the container x
.
val sequence_m : 'a Base.Or_error.t t -> 'a t Base.Or_error.t
sequence_m x
lifts a container of monads x
to a monad containing a container, by sequencing the monadic effects from left to right.