Module Stdlib.Stream

Streams and parsers.

type t(!'a);

The type of streams holding values of type 'a.

exception Failure;

Raised by parsers when none of the first components of the stream patterns is accepted.

exception Error(string);

Raised by parsers when the first component of a stream pattern is accepted, but one of the following components is rejected.

Stream builders

let from: (int => option('a)) => t('a);

Stream.from f returns a stream built from the function f. To create a new stream element, the function f is called with the current stream count. The user function f must return either Some <value> for a value or None to specify the end of the stream.

Do note that the indices passed to f may not start at 0 in the general case. For example, [< '0; '1; Stream.from f >] would call f the first time with count 2.

let of_list: list('a) => t('a);

Return the stream holding the elements of the list in the same order.

let of_string: string => t(char);

Return the stream of the characters of the string parameter.

let of_bytes: bytes => t(char);

Return the stream of the characters of the bytes parameter.

  • since 4.02.0
let of_channel: in_channel => t(char);

Return the stream of the characters read from the input channel.

Stream iterator

let iter: ('a => unit) => t('a) => unit;

Stream.iter f s scans the whole stream s, applying function f in turn to each stream element encountered.

Predefined parsers

let next: t('a) => 'a;

Return the first element of the stream and remove it from the stream.

  • raises Stream.Failure

    if the stream is empty.

let empty: t('a) => unit;

Return () if the stream is empty, else raise Stream.Failure.

Useful functions

let peek: t('a) => option('a);

Return Some of "the first element" of the stream, or None if the stream is empty.

let junk: t('a) => unit;

Remove the first element of the stream, possibly unfreezing it before.

let count: t('a) => int;

Return the current count of the stream elements, i.e. the number of the stream elements discarded.

let npeek: int => t('a) => list('a);

npeek n returns the list of the n first elements of the stream, or all its remaining elements if less than n elements are available.