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Unit ports
This unit contains various extended port definitions. This unit is used by default, unless the program is compiled with the -explicit-use option.
Input/output port extensions
with-output-to-port
[procedure] (with-output-to-port PORT THUNK)Call procedure THUNK with the current output-port temporarily bound to PORT.
make-input-port
[procedure] (make-input-port READ READY? CLOSE [PEEK])Returns a custom input port. Common operations on this port are handled by the given parameters, which should be procedures of no arguments. READ is called when the next character is to be read and should return a character or #!eof. READY? is called when char-ready? is called on this port and should return #t or #f. CLOSE is called when the port is closed. PEEK is called when peek-char is called on this port and should return a character or #!eof. if the argument PEEK is not given, then READ is used instead and the created port object handles peeking automatically (by calling READ and buffering the character).
make-output-port
[procedure] (make-output-port WRITE CLOSE [FLUSH])Returns a custom output port. Common operations on this port are handled by the given parameters, which should be procedures. WRITE is called when output is sent to the port and receives a single argument, a string. CLOSE is called when the port is closed and should be a procedure of no arguments. FLUSH (if provided) is called for flushing the output port.
with-error-output-to-port
[procedure] (with-error-output-to-port PORT THUNK)Call procedure THUNK with the current error output-port temporarily bound to PORT.
with-input-from-port
[procedure] (with-input-from-port PORT THUNK)Call procedure THUNK with the current input-port temporarily bound to PORT.
String-port extensions
call-with-input-string
[procedure] (call-with-input-string STRING PROC)Calls the procedure PROC with a single argument that is a string-input-port with the contents of STRING.
call-with-output-string
[procedure] (call-with-output-string PROC)Calls the procedure PROC with a single argument that is a string-output-port. Returns the accumulated output-string.
with-input-from-string
[procedure] (with-input-from-string STRING THUNK)Call procedure THUNK with the current input-port temporarily bound to an input-string-port with the contents of STRING.
with-output-to-string
[procedure] (with-output-to-string THUNK)Call procedure THUNK with the current output-port temporarily bound to a string-output-port and return the accumulated output string.
Port iterators
port-for-each
[procedure] (port-for-each FN THUNK)Apply FN to successive results of calling the zero argument procedure THUNK until it returns #!eof, discarding the results.
port-map
[procedure] (port-map FN THUNK)Apply FN to successive results of calling the zero argument procedure THUNK until it returns #!eof, returning a list of the collected results.
port-fold
[procedure] (port-fold FN ACC THUNK)Apply FN to successive results of calling the zero argument procedure THUNK, passing the ACC value as the second argument. The FN result becomes the new ACC value. When THUNK returns #!eof, the last FN result is returned.
copy-port
[procedure] (copy-port FROM TO [READ [WRITE]])Reads all remaining data from port FROM using the reader procedure READ and writes it to port TO using the writer procedure WRITE. READ defaults to read-char and WRITE to write-char. Note that this procedure does not check FROM and TO for being ports, so the reader and writer procedures may perform arbitrary operations as long as they can be invoked as (READ FROM) and (WRITE X TO), respectively. copy-port returns an undefined value.
Funky ports
make-broadcast-port
[procedure] (make-broadcast-port PORT ...)Returns a custom output port that emits everything written into it to the ports given as PORT .... Closing the broadcast port does not close any of the argument ports.
make-concatenated-port
[procedure] (make-concatenated-port PORT1 PORT2 ...)Returns a custom input port that reads its input from PORT1, until it is empty, then from PORT2 and so on. Closing the concatenated port does not close any of the argument ports.
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