NAME

Language::Frink::Eval

DESCRIPTION

This module is a simple wrapper around the Frink interpreter written by Alan Eliasen. As such, it requires a local copy of the Java interpreter and the frink.jar file. For more information on Frink, please see http://futureboy.homeip.net/frinkdocs/. This module works by starting a JVM as a child process, and sending Frink expressions to it via a pipe, and retrieving the results the same way. Also, this module has the ability to function in a restricted mode it attempts to filter "dangerous" expressions, such as functions that read files from local disk, the network, and also commands that may persistantly change the interpreter state.

The list of "dangerous" functions and expressions was derived by reading the Frink documentation, and probably is not complete. If you find commands that get through the filter that should, please report them.

The following functions are not allowed in restricted mode:

lines[]

read[]

eval[]

input[]

select[]

callJava[]

newJava[]

staticJava[]

The following language constructs are not allowed in restricted mode:

Regexes

Function Declarations

Unit display format

Loops

Time display format

Procedure blocks

File inclusion

Class Declaration

METHODS

new(Param1 => ..., etc)

This method will create a new Language::Frink::Eval object, and start up an external Frink interpreter in a JVM. If it encounters any problems when starting the JVM, then it will call die.

CONSTRUCTOR PARAMETERS

These parameters are not case sensitive.

Restricted

This is a boolean value. If it is true, then expressions will be filtered to attempt to prevent "dangerous" expressions from being evaluated.

JavaPath

This specifies the entire commandline to run. This defaults to java -cp frink.jar frink.parser.Frink. If the java interpreter is not in your path, or if the frink.jar is not in your current directory, then you will need to change this.

eval($expression)

This passes the expression that is given to the Frink interpreter, and returns the results as a string. This may return a single string will multiple embedded newlines. If the interpreter's results end in a newline, then it will be removed before returning, to make processing the common case of a single line result easier. If the object is set to Restricted then results will be filtered before evaluation. If it is determined that the expression cannot be evaluated due to policy, then the program will croak with an error message describing why.

FILES

This module requires a Java interpreter and a local copy of frink.jar.

LICENSE

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

See http://www.perl.com/perl/misc/Artistic.html.

AUTHOR

Clayton O'Neill <coneill@oneill.net>