Purely functional streams

Contrarily to OCaml module Stream, these are meant to be used purely functionally. This implies in particular that accessing an element does not discard it.

type +'a t

Type of pure streams.

type 'a node =
  1. | Nil
  2. | Cons of 'a * 'a t

    View type to decompose and build streams.

val empty : 'a t

The empty stream.

val cons : 'a -> 'a t -> 'a t

Append an element in front of a stream.

val thunk : (unit -> 'a node) -> 'a t

Internalize the laziness of a stream.

val is_empty : 'a t -> bool

Whethere a stream is empty.

val peek : 'a t -> 'a node

Return the head and the tail of a stream, if any.

Standard operations

All stream-returning functions are lazy. The other ones are eager.

val app : 'a t -> 'a t -> 'a t

Append two streams. Not tail-rec.

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

Mapping of streams. Not tail-rec.

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

Iteration over streams.

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

Fold over streams.

val concat : 'a t t -> 'a t

Appends recursively a stream of streams.

val map_filter : ('a -> 'b option) -> 'a t -> 'b t

Mixing map and filter. Not tail-rec.

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

concat_map f l is the same as concat (map f l).

val of_list : 'a list -> 'a t

Convert a list into a stream.

val to_list : 'a t -> 'a list

Convert a stream into a list.

val force : 'a t -> 'a t

Forces the whole stream.