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lib/Acme/URM.pm  view on Meta::CPAN

package Acme::URM;
use strict;
use Data::Dumper;

our $VERSION	= '0.02';

use constant	LAST		=> -1;
use constant	THIS		=> -2;
use constant	MAX_STEPS	=> -3;

my $DEBUG   = 0;
sub import {
    foreach (@_) {
        if(/^debug$/) {
            $DEBUG  = 1;
        }
    }
}

sub new {
	my $class	= shift;
	my $self	= {@_};
	$self		= bless $self, $class;
	$self->_init();
	$self
}

sub _init {
	my $self	= shift;
	$self->{registers}	= ();
	$self->{program}	= ();
	$self->{instr_num}	= 0;
	$self->{max_steps}	= -1;	# infinite
}

sub program {
	my $self	= shift;
	push @{$self->{program}}, @_	if scalar @_;
	[$self->{program}]
}

sub clear_program {
	my $self	= shift;
	$self->{program}	= ();
}

sub register {
	my $self	= shift;
	my $n		= shift || 0;
	my $i		= $n;
	foreach (@_) {
		$self->{registers}[$i++]	= $_;
	}
	(defined $self->{registers}[$n]) ? $self->{registers}[$n] : 0
}

sub clear_registers {
	my $self	= shift;
	$self->{registers}	= [];
}

sub clear {
	my $self	= shift;
	$self->clear_program();
	$self->clear_registers();
}

sub run {
	my $self	= shift;
	$self->{instr_num}	= 0;
	$self->{steps_num}	= 0;
	my $run	= 1;
	do {
		my $step	= $self->_step();
		return	$step	if MAX_STEPS == $step;
		$run		= (scalar(@{$self->{program}}) > $step) ? 1 : 0;
	} while( $run );
	_debug( "program executed",
		   "registers: " . Dumper([$self->{registers}]),
		   "",
		  );
	$self->register(0)
}