NAME
Language::Befunge - a Befunge-98 interpreter.
SYNOPSIS
use Language::Befunge;
read_file( "program.bf" );
run_code;
Or, one can write directly:
store_code( <<'END_OF_CODE' );
v @,,,,"foo"a <
> ^
END_OF_CODE
run_code;DESCRIPTION
Enter the realm of topological languages!
This module implements the Funge-98 specifications on a 2D field (also called Befunge). In particular, be aware that this is not 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
vThis 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).
PRIVATE FUNCTIONS
debug( )
Output debug messages.
EXPORTED FUNCTIONS
read_file( filename )
Read a file (given as argument) and store its code.
Side effect: clear the previous code.
store_code( code )
Store the given code in the Lahey space.
Side effect: clear the previous code.
run_code( )
Run the current code. That is, create a new Instruction Pointer and move it around the code.
Return the exit code of the program.
TODO
- o
-
Implement the libraries mechanism: "(" and ")" respectively.
- o
-
Implement a standard/simple mechanism in order to allow user to write their own extensions (aka fingerprints)
- o
-
Maybe rewrite the core loop in order to take benefits of the hash mechanism instead of a giant switch tester.
- o
-
Check all the module docs.
- 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
yinstruction: 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 19th cell pushed by the
yinstruction: what this interpreter pushes on the stack may not be accurate, since this is a module and the main perl application may have already processed the command line.
AUTHOR
Jerome Quelin, <jquelin@cpan.org>
COPYRIGHT
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.