NAME

Acme::Cow::Interpreter - Cow programming language interpreter

SYNOPSIS

use Acme::Cow::Interpreter;

my $cow = Acme::Cow::Interpreter -> new();
$cow -> parse_file($file);
$cow -> execute();

ABSTRACT

This module implements an interpreter for the Cow programming language.

DESCRIPTION

This module implements an interpreter for the Cow programming language. The Cow programming language is a so-called esoteric programming language, with only 12 commands.

METHODS

• new()

  Return a new Cow interpreter.

• init()

  Initialize an object instance. Clears the memory and register and sets the memory pointer to zero. Also, the internally stored program source is cleared.

• copy()

  Copy (clone) an Acme::Cow::Interpreter object.

• parse_string( STRING )

  Parses the given string and stores the resulting list of codes in the object. The return value is the object itself.

• parse_file( FILENAME )

  Parses the contents of the given file and stores the resulting list of codes in the object. The return value is the object itself.

• dump_mem()

  Returns a nicely formatted string showing the current memory state.

• dump_obj()

  Returns a text version of object structure.

• execute()

  Executes the source code. The return value is the object itself.

NOTES

The Cow Language

The Cow language has 12 instruction. The commands and their corresponding code numbers are:

• moo (0)

  This command is connected to the MOO command. When encountered during normal execution, it searches the program code in reverse looking for a matching MOO command and begins executing again starting from the found MOO command. When searching, it skips the command that is immediately before it (see MOO).

• mOo (1)

  Moves current memory position back one block.

• moO (2)

  Moves current memory position forward one block.

• mOO (3)

  Execute value in current memory block as if it were an instruction. The command executed is based on the instruction code value (for example, if the current memory block contains a 2, then the moO command is executed). An invalid command exits the running program. Value 3 is invalid as it would cause an infinite loop.

• Moo (4)

  If current memory block has a 0 in it, read a single ASCII character from the standard input and store it in the current memory block. If the current memory block is not 0, then print the ASCII character that corresponds to the value in the current memory block to the standard output.

• MOo (5)

  Decrement current memory block value by 1.

• MoO (6)

  Increment current memory block value by 1.

• MOO (7)

  If current memory block value is 0, skip next command and resume execution after the next matching moo command. If current memory block value is not 0, then continue with next command. Note that the fact that it skips the command immediately following it has interesting ramifications for where the matching moo command really is. For example, the following will match the second and not the first moo: OOO MOO moo moo

• OOO (8)

  Set current memory block value to 0.

• MMM (9)

  If no current value in register, copy current memory block value. If there is a value in the register, then paste that value into the current memory block and clear the register.

• OOM (10)

  Print value of current memory block to the standard output as an integer.

• oom (11)

  Read an integer from the standard input and put it into the current memory block.

TODO

Add more tests. The module is far from being tested thoroughly.

BUGS

There are currently no known bugs.

Please report any bugs or feature requests via https://github.com/pjacklam/p5-Acme-Cow-Interpreter/issues.

Old bug reports and feature requests can be found at http://rt.cpan.org/NoAuth/Bugs.html?Dist=Acme-Cow-Interpreter.

SUPPORT

You can find documentation for this module with the perldoc command.

perldoc Acme::Cow::Interpreter

You can also look for information at:

• GitHub

  http://rt.cpan.org/NoAuth/Bugs.html?Dist=Acme-Cow-Interpreter

• MetaCPAN

  https://metacpan.org/release/Acme-Cow-Interpreter

• CPAN Ratings

  http://cpanratings.perl.org/d/Acme-Cow-Interpreter

• CPAN Testers PASS Matrix

  http://pass.cpantesters.org/distro/A/Acme-Cow-Interpreter.html

• CPAN Testers Reports

  http://www.cpantesters.org/distro/A/Acme-Cow-Interpreter.html

• CPAN Testers Matrix

  http://matrix.cpantesters.org/?dist=Acme-Cow-Interpreter

REFERENCES

• http://bigzaphod.github.io/COW/

AUTHOR

Peter John Acklam <pjacklam@gmail.com<gt>

COPYRIGHT & LICENSE

Copyright 2007-2020 Peter John Acklam.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.0 or, at your option, any later version of Perl 5 you may have available.