A port class. A port is Scheme's way of abstraction of I/O channel.
Gauche extends a port in number of ways so that it can be used
in wide range of applications.
Standard Scheme (R5RS) essentially defines a port as an entity that
you can fetch a character at a time and
look one character ahead from an input port,
and put a character at a time to an output port.
Other R5RS I/O routines can be built on top of them.
Besides this basics, Gauche's port can handle the following
- Byte I/O
- You can read/write one byte at a time, instead of a character.
(Remember, Gauche handles multibyte characters, so a character
may be consisted from more than one bytes).
Most ports allow you to mix byte I/O and character I/O, if needed.
- Block I/O
- You can read/write a specified number of byte sequences.
This can be an efficient way of moving block of data,
if the port's underlying implementation supports block I/O
operation (for example, if the underyling port is a unix buffered
stream, this operation uses
- Some ports can be used to convert a data stream from one format
to another; one of such applications is character code conversion
ports, provided by
(See section 9.2
gauche.charconv - Character Code Conversion, for details).
You can define a procedural ports, in both Scheme and C,
to implement other functionality.