AI-Prolog

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Changes  view on Meta::CPAN

0.03  Sun Jan 23, 2005
      Added tests for built-in predicates.

      Added query() function to AI::Logic::Engine to allow successive queries
        without a new bootstrap.

0.02  Sun Jan 23, 2005
      First public release of AI::Prolog.

0.01  Thu Jan 20 20:47:49 PST 2005
	  original version; created by make_project 0.1

lib/AI/Prolog.pm  view on Meta::CPAN

 aiprolog data/spider.pro
 aiprolog data/sleepy.pro

When the C<aiprolog> shell starts, you can type C<start.> to see how to play
the game.  Typing C<halt.> and hitting return twice will allow you to exit.

See the C<bin/> and C<data/> directories in the distribution.

Additionally, you can read L<AI::Prolog::Article> for a better description of
how to use C<AI::Prolog>.  This document is an article originally published in
The Perl Review (L<http://www.theperlreview.com/>) and which they have
graciously allowed me to redistribute.

See also Robert Pratte's perl.com article, "Logic Programming with Perl and
Prolog" (L<http://www.perl.com/pub/a/2005/12/15/perl_prolog.html>) for more
more examples.

=head1 DESCRIPTION

C<AI::Prolog> is a pure Perl predicate logic engine.  In predicate logic,

lib/AI/Prolog/Article.pod  view on Meta::CPAN

 loves(ovid, prolog).
 loves(ovid, 'Perl 6').

(The quotes around "Perl 6" tell Prolog that this is a single value and that
it's a constant, not a variable.)

How do I find out everything Ovid loves?  In Prolog, the query doesn't change:

 loves(ovid, WHAT).

In Perl, our original hash wasn't enough.

 my %loves = (
     ovid    => [ qw/perl prolog Perl6/ ],
     alice   => [ 'perl' ],
     bob     => [ 'perl' ],
     charlie => [ 'perl' ],
 );

 my %who_loves;
 while ( my ($person, $things) = each %loves ) {

lib/AI/Prolog/Engine.pm  view on Meta::CPAN

 my $database = Parser->consult($some_prolog_program);
 my $query    = Term->new('steals(badguy, X).');
 my $engine   = Engine->new($query, $database);
 Engine->formatted(1);
 while (my $results = $engine->results) {
    print $results, $/;
 }

The need to have a query at the same time you're instantiating the engine is a
bit of a drawback based upon the original W-Prolog work.  I will likely remove
this drawback in the future.

=head2 C<formatted([$boolean])>

The default value of C<formatted> is true.  This method, if passed a true
value, will cause C<results> to return a nicely formatted string representing
the output of the program.  This string will loosely correspond with the
expected output of a Prolog program.

If false, all calls to C<result> will return Perl data structures instead of