19.29 Module Stream: streams and parsers

type 'a t
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 of string;;
Raised by parsers when the first component of a stream pattern is accepted, but one of the following components is rejected.
Stream builders
Warning: these functions create streams with fast access; it is illegal to mix them with streams built with [< >]; would raise Failure when accessing such mixed streams.
val from : (int -> 'a option) -> 'a t;;
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.
val of_list : 'a list -> 'a t;;
Return the stream holding the elements of the list in the same order.
val of_string : string -> char t;;
Return the stream of the characters of the string parameter.
val of_channel : in_channel -> char t;;
Return the stream of the characters read from the input channel.
Stream iterator
val iter : f:('a -> unit) -> 'a t -> unit;;
Stream.iter f s scans the whole stream s, applying function f in turn to each stream element encountered.
Predefined parsers
val next : 'a t -> 'a;;
Return the first element of the stream and remove it from the stream. Raise Stream.Failure if the stream is empty.
val empty : 'a t -> unit;;
Return () if the stream is empty, else raise Stream.Failure.
Useful functions
val peek : 'a t -> 'a option;;
Return Some of "the first element" of the stream, or None if the stream is empty.
val junk : 'a t -> unit;;
Remove the first element of the stream, possibly unfreezing it before.
val count : 'a t -> int;;
Return the current count of the stream elements, i.e. the number of the stream elements discarded.
val npeek : int -> 'a t -> 'a list;;
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.