package lwt

Type of a stream holding values of type 'a

from f creates an stream from the given input function. f is called each time more input is needed, and the stream ends when f returns None.

from_direct f does the same as from but with a function that does not return a thread. It is better than wrapping f into a function which returns a thread.

Exception raised by the push function of a push-stream when pushing an element after the end of stream (= None) have been pushed.

create () returns a new stream and a push function.

create_with_reference () returns a new stream and a push function. The last function allows a reference to be set to an external source. This prevents the external source from being garbage collected.

For example, to convert a reactive event to a stream:

let stream, push, set_ref = Lwt_stream.create_with_reference () in
set_ref (map_event push event)

Exception raised by the push function of a bounded push-stream when the stream queue is full and a thread is already waiting to push an element.

Type of sources for bounded push-streams.

create_bounded size returns a new stream and a bounded push source. The stream can hold a maximum of size elements. When this limit is reached, pushing a new element will block until one is consumed.

Note that you cannot clone or parse (with parse) a bounded stream. These functions will raise Invalid_argument if you try to do so.

It raises Invalid_argument if size < 0.

of_list l creates a stream returning all elements of l

of_array a creates a stream returning all elements of a

of_string str creates a stream returning all characters of str

clone st clone the given stream. Operations on each stream will not affect the other.

For example:

# let st1 = Lwt_stream.of_list [1; 2; 3];;
val st1 : int Lwt_stream.t = <abstr>
# let st2 = Lwt_stream.clone st1;;
val st2 : int Lwt_stream.t = <abstr>
# lwt x = Lwt_stream.next st1;;
val x : int = 1
# lwt y = Lwt_stream.next st2;;
val y : int = 1

It raises Invalid_argument if st is a bounded push-stream.

Returns the list of elements of the given stream

Returns the word composed of all characters of the given stream

Exception raised when trying to retreive data from an empty stream.

peek st returns the first element of the stream, if any, without removing it.

npeek n st returns at most the first n elements of st, without removing them.

get st remove and returns the first element of the stream, if any.

nget n st remove and returns at most the first n elements of st.

get_while f st returns the longest prefix of st where all elements satisfy f.

next st remove and returns the next element of the stream, of fail with Empty if the stream is empty.

last_new st returns the last element that can be obtained without sleepping, or wait for one if no one is already available.

If fails with Empty if the stream has no more elements

junk st remove the first element of st.

njunk n st removes at most the first n elements of the stream.

junk_while f st removes all elements at the beginning of the streams which satisfy f.

junk_old st removes all elements that are ready to be read without yeilding from st.

For example the read_password function of Lwt_read_line use that to junk key previously typed by the user.

get_available st returns all available elements of l without blocking

get_available_up_to n st returns up to n elements of l without blocking

is_empty st returns wether the given stream is empty

on_termination st f executes f when the end of the stream st is reached. Note that the stream may still contains elements if peek or similar was used.

choose l creates an stream from a list of streams. The resulting stream will returns elements returned by any stream of l in an unspecified order.

map f st maps the value returned by st with f

filter f st keeps only value x such that f x is true

filter_map f st filter and map st at the same time

map_list f st applies f on each element of st and flattens the lists returned

fold f s x fold_like function for streams.

iter f s iterates over all elements of the stream

find f s find an element in a stream.

find f s find and map at the same time.

combine s1 s2 combine two streams. The stream will ends when the first stream ends.

append s1 s2 returns a stream which returns all elements of s1, then all elements of s2

concat st returns the concatenation of all streams of st.

flatten st = map_list (fun l -> l) st

A value or an error.

map_exn s returns a stream that captures all exceptions raised by the source of the stream (the function passed to from).

Note that for push-streams (as returned by create) all elements of the mapped streams are values.

parse st f parses st with f. If f raise an exception, st is restored to its previous state.

It raises Invalid_argument if st is a bounded push-stream.

hexdump byte_stream returns a stream which is the same as the output of hexdump -C.

Basically, here is a simple implementation of hexdump -C:

let () = Lwt_main.run (Lwt_io.write_lines Lwt_io.stdout (Lwt_stream.hexdump (Lwt_io.read_lines Lwt_io.stdin)))