package travesty

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Monadically traversable containers

Install

Dune Dependency

mattwindsor91.github.io Readme Changelog Edit opam file Versions (8)

Authors

M

Matt Windsor <m.windsor@imperial.ac.uk>

Maintainers

M

Matt Windsor <m.windsor@imperial.ac.uk>

Sources

travesty-v0.3.0.tbz

sha256=40ada5c475cfeba7d933eec133294d1b5ef5da6ce864c9746b2ce4ce49b5e3a4

md5=dc818d6b232f13edb388d25781cd99a2

doc/travesty/Travesty/T_list/index.html

Module `Travesty.T_list`Source

List extensions.

This module contains various extensions for Core's List module, including adding monadic traversal.

Sourcetype 'a t = 'a Base.list

t is just list, re-exported to make this module satisfy various container interfaces.

Lists are traversable containers.

include Traversable.S1_container with type 'a t := 'a t

Source

module On_monad
  (M : Base.Monad.S) : 
  Traversable.On_monad1 with type 'a t := 'a t and module M := M

On_monad implements monadic folding and mapping operators for a given monad M, including arity-1 specific operators.

Source

module With_errors : 
  Traversable.On_monad1 with type 'a t := 'a t and module M := Base.Or_error

With_errors is shorthand for On_monad (Or_error).

include Traversable.Generic_container
  with type 'a t := 'a t
   and type 'a elt := 'a
   and module On_monad := On_monad
   and module With_errors := With_errors

include Types_intf.Generic with type 'a t := 'a t with type 'a elt := 'a

We can do generic container operations.

include Base.Container.Generic with type 'a t := 'a t and type 'a elt := 'a

We can do non-monadic mapping operations.

include Mappable.Generic with type 'a t := 'a t and type 'a elt := 'a

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 Types_intf.Generic with type 'a t := 'a t with type 'a elt := 'a

Sourceval fold_map : 'a t -> f:('acc -> 'a -> 'acc * 'b) -> init:'acc -> 'acc * 'b t

fold_map c ~f ~init folds f over every t in c, threading through an accumulator with initial value init.

Sourceval mapi : f:(Base.int -> 'a -> 'b) -> 'a t -> 'b t

mapi ~f t maps f across t, passing in an increasing position counter.

include Mappable.S1_container with type 'a t := 'a t

include Mappable.S1 with type 'a t := 'a t

include Mappable.Generic with type 'a t := 'a t and type 'a elt := 'a

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 Types_intf.Generic with type 'a t := 'a t with type 'a elt := 'a

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

map c ~f maps f over every t in c.

include Base.Container.S1 with type 'a t := 'a t

val mem : 'a t -> 'a -> equal:('a -> 'a -> bool) -> bool

val length : 'a t -> int

val is_empty : 'a t -> bool

val iter : 'a t -> f:('a -> unit) -> unit

val fold : 'a t -> init:'accum -> f:('accum -> 'a -> 'accum) -> 'accum

val fold_result : 
  'a t ->
  init:'accum ->
  f:('accum -> 'a -> ('accum, 'e) Base__.Result.t) ->
  ('accum, 'e) Base__.Result.t

val fold_until : 
  'a t ->
  init:'accum ->
  f:('accum -> 'a -> ('accum, 'final) Base__Container_intf.Continue_or_stop.t) ->
  finish:('accum -> 'final) ->
  'final

val exists : 'a t -> f:('a -> bool) -> bool

val for_all : 'a t -> f:('a -> bool) -> bool

val count : 'a t -> f:('a -> bool) -> int

val sum : 
  (module Base__Container_intf.Summable with type t = 'sum) ->
  'a t ->
  f:('a -> 'sum) ->
  'sum

val find : 'a t -> f:('a -> bool) -> 'a option

val find_map : 'a t -> f:('a -> 'b option) -> 'b option

val to_list : 'a t -> 'a list

val to_array : 'a t -> 'a array

val min_elt : 'a t -> compare:('a -> 'a -> int) -> 'a option

val max_elt : 'a t -> compare:('a -> 'a -> int) -> 'a option

include Mappable.Extensions1 with type 'a t := 'a t

Extensions1 includes the container extensions from T_container, as they work with any arity-1 container.

include T_container.Extensions1 with type 'a t := 'a t

include T_container.Generic_extensions
  with type 'a t := 'a t
   and type 'a elt := 'a

Generic_extensions 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 Types_intf.Generic with type 'a t := 'a t with type 'a elt := 'a

Testing for a specific number of elements

The following functions help in checking whether a container has a particular, commonly-required number of elements (zero or one, one, two, and so on).

Sourceval at_most_one : 'a t -> 'a Base.option Base.Or_error.t

at_most_one xs returns Ok None if xs is empty; Ok Some(x) if it contains only x; and an error otherwise.

Examples:

  T_list.at_most_one []     (* ok None *)
         at_most_one [1]    (* ok (Some 1) *)
         at_most_one [1; 2] (* error -- too many *)

Sourceval one : 'a t -> 'a Base.Or_error.t

one xs returns Ok x if xs contains only x, and an error otherwise.

Examples:

  T_list.one []     (* error -- not enough *)
         one [1]    (* ok 1 *)
         one [1; 2] (* error -- too many *)

Sourceval two : 'a t -> ('a * 'a) Base.Or_error.t

two xs returns Ok (x, y) if xs is a list containing only x and y in that order, and an error otherwise.

Examples:

  T_list.two []        (* error -- not enough *)
         two [1]       (* error -- not enough *)
         two [1; 2]    (* ok (1, 2) *)
         two [1; 2; 3] (* error -- too many *)

Miscellaneous extensions

Source

val max_measure : 
  measure:('a -> Base.int) ->
  ?default:Base.int ->
  'a t ->
  Base.int

max_measure ~measure ~default xs measures each item in xs according to measure, and returns the highest measure reported. If xs is empty, return default if given, and 0 otherwise.

Predicate extensions are available on all arity-1 containers, provided that we fix the element type parameter to 'a -> bool.

include T_container.Generic_predicate_extensions
  with type 'a t := ('a -> Base.bool) t
   and type 'a item := 'a

Sourceval any : 'a -> predicates:('a -> Base.bool) t -> Base.bool

any x ~predicates tests x against predicates until one returns true, in which case it returns true; or all return false, in which case it returns false.

Sourceval all : 'a -> predicates:('a -> Base.bool) t -> Base.bool

any x ~predicates tests x against predicates until one returns false, in which case it returns false; or all return true, in which case it returns true.

Sourceval none : 'a -> predicates:('a -> Base.bool) t -> Base.bool

none x ~predicates is the same as any x with all predicates in predicates negated. It tests x against predicates until one returns true, in which case it returns false; or all return false, in which case it returns true.

Sourceval right_pad : padding:'a -> 'a Base.list t -> 'a Base.list t

right_pad ~padding xs pads every list in xs with padding, ensuring all lists have equal length.

Example:

  right_pad ~padding:6
    [ [0; 8; 0; 0]    (* [ [ 0; 8; 0; 0; 6 ] *)
    ; [9; 9; 9]       (* ; [ 9; 9; 9; 6; 6 ] *)
    ; [8; 8; 1; 9; 9] (* ; [ 8; 8; 1; 9; 9 ] *)
    ; [9; 1; 1; 9]    (* ; [ 9; 1; 1; 9; 6 ] *)
    ; [7; 2; 5]       (* ; [ 7; 2; 5; 6; 6 ] *)
    ; [3]             (* ; [ 3; 6; 6; 6; 6 ] *)
    ]                 (* ] *)

Source

module With_elt
  (Elt : Base.Equal.S) : 
  Traversable.S0_container with type t := Elt.t t and module Elt = Elt

With_elt (Elt) demotes this S1_container to a S0_container by fixing the element type to that mentioned in Elt.

We can also filter-map over them.

include Filter_mappable.S1 with type 'a t := 'a t

include Filter_mappable.Generic with type 'a t := 'a t and type 'a elt := 'a

Generic strictly extends Generic_basic.

include Filter_mappable.Generic_basic
  with type 'a t := 'a t
  with type 'a elt := 'a

Generic_basic 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 Types_intf.Generic with type 'a t := 'a t with type 'a elt := 'a

Sourceval filter_map : 'a t -> f:('a -> 'b Base.option) -> 'b t

filter_map c ~f maps f over every t in c, discarding any items for which f returns None.

Sourceval filter : 'a t -> f:('a -> Base.bool) -> 'a t

filter c ~f checks f over every t in c, discarding any items for which f returns false.

Sourceval exclude : 'a t -> f:('a -> Base.bool) -> 'a t

exclude c ~f checks f over every t in c, discarding any items for which f returns true.

We can also derive Mappable interfaces from filter-mappable ones, but leave that to a separate functor.

Miscellaneous extension functions

Sourceval prefixes : 'a t -> 'a t t

prefixes xs returns all non-empty prefixes of xs.

Examples:

  prefixes [1; 2; 3] (* [ [ 1 ]; [ 1; 2 ]; [ 1; 2; 3 ] *)

On This Page

Miscellaneous extension functions

package travesty

Install

Dune Dependency

Authors

Maintainers

Sources

doc/travesty/Travesty/T_list/index.html

Module Travesty.T_listSource

Testing for a specific number of elements

Miscellaneous extensions

Miscellaneous extension functions

Module `Travesty.T_list`Source