module Stream: sig .. end
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
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.
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
.
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 : Pervasives.in_channel -> char t
Return the stream of the characters read from the input channel.
Stream iterator
val iter : ('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.