Module Gen

module Gen: sig .. end


Values of type 'a Gen.t represent a possibly infinite sequence of values of type 'a. One can only iterate once on the sequence, as it is consumed by iteration/deconstruction/access. None is returned when the generator is exhausted.

The submodule Gen.Restart provides utilities to work with restartable generators, that is, functions unit -> 'a Gen.t that allow to build as many generators from the same source as needed.

Global type declarations

type 'a t = unit -> 'a option 

A generator may be called several times, yielding the next value each time. It returns None when no elements remain

type 'a gen = 'a t 
module type S = Gen_intf.S

Transient generators

val get : 'a t -> 'a option

Get the next value

val next : 'a t -> 'a option

Synonym for Gen.get

val get_exn : 'a t -> 'a

Get the next value, or fails

val junk : 'a t -> unit

Drop the next value, discarding it.

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

Call the same function an infinite number of times (useful for instance if the function is a random generator).

include Gen.S

Operations on transient generators

Restartable generators

A restartable generator is a function that produces copies of the same generator, on demand. It has the type unit -> 'a gen and it is assumed that every generated returned by the function behaves the same (that is, that it traverses the same sequence of elements).

module Restart: sig .. end


val persistent : 'a t -> 'a Restart.t

Store content of the transient generator in memory, to be able to iterate on it several times later. If possible, consider using combinators from Gen.Restart directly instead.

val persistent_lazy : ?caching:bool -> ?max_chunk_size:int -> 'a t -> 'a Restart.t

Same as Gen.persistent, but consumes the generator on demand (by chunks). This allows to make a restartable generator out of an ephemeral one, without paying a big cost upfront (nor even consuming it fully). Optional parameters: see GenMList.of_gen_lazy.

val peek : 'a t -> ('a * 'a option) t

peek g transforms the generator g into a generator of x, Some next if x was followed by next in g, or x, None if x was the last element of g

val peek_n : int -> 'a t -> ('a * 'a array) t

peek_n n g iterates on g, returning along with each element the array of the (at most) n elements that follow it immediately

val start : 'a Restart.t -> 'a t

Create a new transient generator. start gen is the same as gen () but is included for readability.

Basic IO

Very basic interface to manipulate files as sequence of chunks/lines.

module IO: sig .. end