Jess File I/O Functions

List of file input/output functions that can be executed by Jess.

8.31. (close [<router-identifier>])

Package:
Intrinsics
Arguments:
One or more router identifiers (atoms)
Returns:
TRUE
Description:
Closes any I/O routers associated with the given name by calling close() on the underlying stream, then removes the routers. Any subsequent attempt to use a closed router will report bad router. See open.

8.60. (format <router-identifier> <string-expression> <expression>*)

Package:
MiscFunctions
Arguments:
A router identifier, a format string, and zero or more arguments
Returns:
A string
Description:
Sends formatted output to the specified logical name. Formats the arguments into a string according to the format string, which is identical to that used by printf in the C language (find a C book for more information). Returns the string, and optionally prints the string to the named router. If you pass nil for the router name, no printing is done.

8.64. (get-multithreaded-io)

Package:
Intrinsics
Arguments:
None
Returns:
Boolean
Description:
Returns TRUE is Jess is currently using a separate thread to flush I/O streams. Turning this on can lead to a modest performance enhancement, at the expense of possible loss of output on program termination.

8.101. (open <file-name> <router-identifier> [r|w|a])

Package:
Intrinsics
Arguments:
A file name, an identifier for the file (an atom), and optionally a mode string, one of r, w, a.
Returns:
The file identifier, a router name.
Description:
Opens a file. Subsequently, the given router identifier can be passed to printout, read, readline, or any other functions that accept I/O routers as arguments. By default, the file is opened for reading; if a mode string is given, it may be opened for reading only (r), writing only (w), or appending (a).

Note: See the batch command for a discussion about specifying filenames in Jess.

8.108. (printout <router-identifier> <expression>*)

Package:
Intrinsics
Arguments:
A router identifier followed by zero or more expressions
Returns:
nil
Description:
Sends unformatted output to the specified logical name. Prints its arguments to the named router, which must be open for output. No spaces are added between arguments. The special atom crlf prints as a newline. The special router name t can be used to signify standard output.

8.111. (read [<router-identifier>])

Package:
Intrinsics
Arguments:
An optional input router identifier (when omitted t is the default)
Returns:
(Varies)
Description:
Reads a single-field value from a specified logical name. Read a single atom, string, or number from the named router, returns this value. The router t means standard input. Newlines are treated as ordinary whitespace; this behaviour is different than in CLIPS, which returns newlines as tokens. If you need to parse text line-by-line, use readline and explode$.

8.112. (readline [<router-identifier>])

Package:
Intrinsics
Arguments:
An optional input router identifier (when omitted t is the default)
Returns:
String
Description:
Reads an entire line as a string from the specified logical name (router). The router t means standard input.

8.128. (set-multithreaded-io (TRUE | FALSE))

Package:
Intrinsics
Arguments:
Boolean
Returns:
Boolean
Description:
Specify whether Jess should use a separate thread to flush I/O streams. Turning this on can lead to a modest performance enhancement, at the expense of possible loss of output on program termination. Returns the previous value of this property.

8.137. (socket <Internet-hostname> <TCP-port-number> <router-identifier>)

Package:
MiscFunctions
Arguments:
An Internet hostname, a TCP port number, and a router identifier
Returns:
The router identifier
Description:
Somewhat equivalent to open, except that instead of opening a file, opens an unbuffered TCP network connection to the named host at the named port, and installs it as a pair of read and write routers under the given name.