package non_empty_list

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Or_unequal_lengths is used for functions that take multiple non-empty lists (denoted t1, etc). Defines the dependent type: {'a : length t1 = length t2 = ... length tn}. Extends the Base.List.Or_unequal_lengths implementation with the Monad methods, improves readabily and reuseability of other library functions.

include module type of Base.List.Or_unequal_lengths

Or_unequal_lengths is used for functions that take multiple lists and that only make sense if all the lists have the same length, e.g., iter2, map3. Such functions check the list lengths prior to doing anything else, and return Unequal_lengths if not all the lists have the same length.

Or_unequal_lengths is used for functions that take multiple lists and that only make sense if all the lists have the same length, e.g., iter2, map3. Such functions check the list lengths prior to doing anything else, and return Unequal_lengths if not all the lists have the same length.

type 'a t = 'a Base.List.Or_unequal_lengths.t =
  1. | Ok of 'a
  2. | Unequal_lengths
val compare : ('a -> 'a -> int) -> 'a t -> 'a t -> int
val sexp_of_t : ('a -> Sexplib0.Sexp.t) -> 'a t -> Sexplib0.Sexp.t
include Base.Monad.S with type 'a t := 'a t
val (>>=) : 'a t -> ('a -> 'b t) -> 'b t

t >>= f returns a computation that sequences the computations represented by two monad elements. The resulting computation first does t to yield a value v, and then runs the computation returned by f v.

val (>>|) : 'a t -> ('a -> 'b) -> 'b t

t >>| f is t >>= (fun a -> return (f a)).

module Monad_infix : sig ... end
val bind : 'a t -> f:('a -> 'b t) -> 'b t

bind t ~f = t >>= f

val return : 'a -> 'a t

return v returns the (trivial) computation that returns v.

val map : 'a t -> f:('a -> 'b) -> 'b t

map t ~f is t >>| f.

val join : 'a t t -> 'a t

join t is t >>= (fun t' -> t').

val ignore_m : 'a t -> unit t

ignore_m t is map t ~f:(fun _ -> ()). ignore_m used to be called ignore, but we decided that was a bad name, because it shadowed the widely used Stdlib.ignore. Some monads still do let ignore = ignore_m for historical reasons.

val all : 'a t list -> 'a list t
val all_unit : unit t list -> unit t

Like all, but ensures that every monadic value in the list produces a unit value, all of which are discarded rather than being collected into a list.

module Let_syntax : sig ... end

These are convenient to have in scope when programming with a monad: