The London Perl and Raku Workshop takes place on 26th Oct 2024. If your company depends on Perl, please consider sponsoring and/or attending.


Language::Befunge - a generic funge interpreter


version 5.000


    use Language::Befunge;
    my $interp = Language::Befunge->new( { file => '' } );
    $interp->run_code( "param", 7, "foo" );

    Or, one can write directly:
    my $interp = Language::Befunge->new;
    $interp->store_code( <<'END_OF_CODE' );
    < @,,,,"foo"a


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 n-funge implementation (3D and more).

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
                      |         x
  -2,147,483,648      |      2,147,483,647

This module also implements the Concurrent Funge semantics.


new( [params] )

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


Although this module comes with a full set of tests, there may be subtle bugs remaining - or maybe I misinterpreted the Funge-98 specs. Please report any bugs or feature requests to "bug-language-befunge at", or through the web interface at <>. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

Here is a list of known "bugs", coming from the specs:


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.


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.


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

Thanks also to Matti Niemenmaa for his mycology test suite, available at


You can find more information on Befunge at

Our git repository is located at

You can also look for information on this module at:


Jerome Quelin


This software is copyright (c) 2003 by Jerome Quelin.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.