Language::Befunge.3pm

Langue: en

Version: 2008-01-22 (mandriva - 01/05/08)

Section: 3 (Bibliothèques de fonctions)

Sommaire

NAME

Language::Befunge - a Befunge-98 interpreter

SYNOPSIS

     use Language::Befunge;
     my $interp = Language::Befunge->new( "program.bf" );
     $interp->run_code( "param", 7, "foo" );
 
     Or, one can write directly:
     my $interp = Language::Befunge->new;
     $interp->store_code( <<'END_OF_CODE' );
     < @,,,,"foo"a
     END_OF_CODE
     $interp->run_code;

DESCRIPTION

Enter the realm of topological languages!

This module implements the Funge-98 specifications on a 2D field (also called Befunge). It can also work as a Trefunge implementation (3D).

This Befunge-98 interpreters assumes the stack and Funge-Space cells of this implementation are 32 bits signed integers (I hope your os understand those integers). This means that the torus (or Cartesian Lahey-Space topology to be more precise) looks like the following:

               32-bit Befunge-98
               =================
                       ^
                       |-2,147,483,648
                       |
                       |         x
           <-----------+----------->
   -2,147,483,648      |      2,147,483,647
                       |
                      y|2,147,483,647
                       v

This implementation is meant to work on unix-like systems, because this interpreters only handle the character which ordinal value is 10 (also known as \n) as an End-Of-Line chars. In particular, no warranty is made neither for Microsoft systems (\r\n) nor for Macs (\r).

This module also implements the Concurrent Funge semantics.

PUBLIC METHODS


new( [params] )

Call directly the Language::Befunge::Interpreter constructor. Refer to Language::Befunge::Interpreter for more information.

TODO

o
Write standard libraries.

BUGS

Although this module comes with a full set of tests, maybe there are subtle bugs - or maybe even I misinterpreted the Funge-98 specs. Please report them to me.

There are some bugs anyway, but they come from the specs:

o
About the 18th cell pushed by the "y" instruction: Funge specs just tell to push onto the stack the size of the stacks, but nothing is said about how user will retrieve the number of stacks.
o
About the load semantics. Once a library is loaded, the interpreter is to put onto the TOSS the fingerprint of the just-loaded library. But nothing is said if the fingerprint is bigger than the maximum cell width (here, 4 bytes). This means that libraries can't have a name bigger than 0x80000000, ie, more than four letters with the first one smaller than "P" ("chr(80)").

Since perl is not so rigid, one can build libraries with more than four letters, but perl will issue a warning about non-portability of numbers greater than 0xffffffff.

ACKNOWLEDGEMENTS

I would like to thank Chris Pressey, creator of Befunge, who gave a whole new dimension to both coding and obfuscating.

SEE ALSO

perl
<http://www.catseye.mb.ca/esoteric/befunge/>
<http://dufflebunk.iwarp.com/JSFunge/spec98.html>

AUTHOR

Jerome Quelin, <jquelin@cpan.org>

Development is discussed on <language-befunge@mongueurs.net>

Copyright (c) 2001-2008 Jerome Quelin, all rights reserved.

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