module Scanning: sig .. end
type in_channel
The notion of input channel for the Scanf
module:
those channels provide all the machinery necessary to read from a given
Pervasives.in_channel
value.
A Scanf.Scanning.in_channel
value is also called a formatted input
channel or equivalently a scanning buffer.
The type scanbuf
below is an alias for in_channel
.
Since 3.12.0
type scanbuf = in_channel
The type of scanning buffers. A scanning buffer is the source from which a
formatted input function gets characters. The scanning buffer holds the
current state of the scan, plus a function to get the next char from the
input, and a token buffer to store the string matched so far.
Note: a scanning action may often require to examine one character in
advance; when this 'lookahead' character does not belong to the token
read, it is stored back in the scanning buffer and becomes the next
character yet to be read.
val stdin : in_channel
The standard input notion for the Scanf
module.
Scanning.stdin
is the formatted input channel attached to
Pervasives.stdin
.
Note: in the interactive system, when input is read from stdin
, the
newline character that triggers the evaluation is incorporated in the
input; thus, the scanning specifications must properly skip this
additional newline character (for instance, simply add a '\n'
as the
last character of the format string).
Since 3.12.0
type file_name = string
A convenient alias to designate a file name.
Since 4.00.0
val open_in : file_name -> in_channel
Scanning.open_in fname
returns a formatted input channel for bufferized
reading in text mode from file fname
.
Note:
open_in
returns a formatted input channel that efficiently reads
characters in large chunks; in contrast, from_channel
below returns
formatted input channels that must read one character at a time, leading
to a much slower scanning rate.
Since 3.12.0
val open_in_bin : file_name -> in_channel
Scanning.open_in_bin fname
returns a formatted input channel for
bufferized reading in binary mode from file fname
.
Since 3.12.0
val close_in : in_channel -> unit
Closes the Pervasives.in_channel
associated with the given
Scanning.in_channel
formatted input channel.
Since 3.12.0
val from_file_bin : string -> in_channel
An alias for open_in_bin
above.
val from_string : string -> in_channel
Scanning.from_string s
returns a formatted input channel which reads
from the given string.
Reading starts from the first character in the string.
The end-of-input condition is set when the end of the string is reached.
val from_function : (unit -> char) -> in_channel
Scanning.from_function f
returns a formatted input channel with the
given function as its reading method.
When scanning needs one more character, the given function is called.
When the function has no more character to provide, it must signal an
end-of-input condition by raising the exception End_of_file
.
val from_channel : Pervasives.in_channel -> in_channel
Scanning.from_channel ic
returns a formatted input channel which reads
from the regular input channel ic
argument, starting at the current
reading position.
val end_of_input : in_channel -> bool
Scanning.end_of_input ic
tests the end-of-input condition of the given
formatted input channel.
val beginning_of_input : in_channel -> bool
Scanning.beginning_of_input ic
tests the beginning of input condition of
the given formatted input channel.
val name_of_input : in_channel -> string
Scanning.name_of_input ic
returns the name of the character source
for the formatted input channel ic
.
Since 3.09.0
val stdib : in_channel
A deprecated alias for Scanning.stdin
, the scanning buffer reading from
Pervasives.stdin
.