package travesty

  1. Overview
  2. Docs
Legend:
Library
Module
Module type
Parameter
Class
Class type

Extend1 creates Extensions for a Container.S1.

Parameters

Signature

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

Containers of predicates

The following functions concern containers of predicates (functions of type 'a -> bool).

val any : 'a -> predicates:('a -> bool) C.t -> 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.

val all : 'a -> predicates:('a -> bool) C.t -> 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.

val none : 'a -> predicates:('a -> bool) C.t -> 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.

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).

val at_most_one : 'a C.t -> 'a option Core_kernel.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 *)
val one : 'a C.t -> 'a Core_kernel.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 *)
val two : 'a C.t -> ('a * 'a) Core_kernel.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 *)
OCaml

Innovation. Community. Security.