Module Const.OnSource

On implements traversal operators for a given applicative M.

Parameters

Signature

include Traversable_types.Basic_generic_on_applicative with type 'a t := t with type 'a elt := Elt.t with module M := M

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 Generic_types.Generic with type 'a t := t with type 'a elt := Elt.t
Sourceval map_m : t -> f:(Elt.t -> Elt.t M.t) -> t M.t

map_m c ~f maps f over every t in c, threading through an applicative functor.

Example:

  (* Travesty_base_exts.List adds applicative traversals to a list;
     With_errors (in S1_container) implements them on the On_error
     applicative functor. *)

  let f x =
    Or_error.(if 0 < x then error_string "negative!" else ok x)
  in
  List.With_errors.map_m integers ~f
Sourceval iter_m : t -> f:(Elt.t -> Base.unit M.t) -> Base.unit M.t

iter_m x ~f iterates the computation f over x, returning the final applicative effect.