Module IStream

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 =
| Nil
| 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.