Extend1 creates Extensions for a Container.S1.
module C : Core_kernel.Container.S1val max_measure : measure:('a -> int) -> ?default:int -> 'a C.t -> intmax_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.
The following functions concern containers of predicates (functions of type 'a -> bool).
val any : 'a -> predicates:('a -> bool) C.t -> boolany 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 -> boolany 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 -> boolnone 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.
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.tat_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.tone 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.ttwo 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 *)