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lib/AI/ExpertSystem/Simple.pm  view on Meta::CPAN

package AI::ExpertSystem::Simple;

use strict;
use warnings;

use XML::Twig;

use AI::ExpertSystem::Simple::Rule;
use AI::ExpertSystem::Simple::Knowledge;
use AI::ExpertSystem::Simple::Goal;

our $VERSION = '1.2';

sub new {
	my ($class) = @_;

	die "Simple->new() takes no arguments" if scalar(@_) != 1;

	my $self = {};

	$self->{_rules} = ();
	$self->{_knowledge} = ();
	$self->{_goal} = undef;
	$self->{_filename} = undef;

	$self->{_ask_about} = undef;
	$self->{_told_about} = undef;

	$self->{_log} = ();

	$self->{_number_of_rules} = 0;
	$self->{_number_of_attributes} = 0;
	$self->{_number_of_questions} = 0;

	return bless $self, $class;
}

sub reset {
	my ($self) = @_;

	die "Simple->reset() takes no arguments" if scalar(@_) != 1;

	foreach my $name (keys %{$self->{_rules}}) {
		$self->{_rules}->{$name}->reset();
	}

	foreach my $name (keys %{$self->{_knowledge}}) {
		$self->{_knowledge}->{$name}->reset();
	}

	$self->{_ask_about} = undef;
	$self->{_told_about} = undef;
	$self->{_log} = ();
}

sub load {
	my ($self, $filename) = @_;

	die "Simple->load() takes 1 argument" if scalar(@_) != 2;
	die "Simple->load() argument 1 (FILENAME) is undefined" if !defined($filename);

	if(-f $filename and -r $filename) {
		my $twig = XML::Twig->new(
			twig_handlers => { goal => sub { $self->_goal(@_) },
					   rule => sub { $self->_rule(@_) },
					   question => sub { $self->_question(@_) } }
		);

		$twig->safe_parsefile($filename);

		die "Simple->load() XML parse failed: $@" if $@;

		$self->{_filename} = $filename;

		$self->_add_to_log( "Read in $filename" );
		$self->_add_to_log( "There are " . $self->{_number_of_rules} . " rules" );
		$self->_add_to_log( "There are " . $self->{_number_of_attributes} . " attributes" );
		$self->_add_to_log( "There are " . $self->{_number_of_questions} . " questions" );
		$self->_add_to_log( "The goal attibutes is " . $self->{_goal}->name() );
		return 1;
	} else {
		die "Simple->load() unable to use file";
	}
}

sub _goal {
	my ($self, $t, $node) = @_;

	my $attribute = undef;
	my $text = undef;

	my $x = ($node->children('attribute'))[0];
	$attribute = $x->text();

	$x = ($node->children('text'))[0];