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lib/AI/Evolve/Befunge/Critter.pm  view on Meta::CPAN

the config file.  If that can't be found, a default value of 2 is
used.


=item RepeatCost

This is the number of tokens the critter pays for each time a command
is repeated (with the "k" instruction).  It makes sense for this value
to be lower than the IterCost setting, as it is somewhat more
efficient.

If not specified, this will be pulled from the variable "repeatcost"
in the config file.  If that can't be found, a default value of 1 is
used.


=item StackCost

This is the number of tokens the critter pays for each time a value
is pushed onto the stack.  It also has an effect when the critter
creates a new stack; the number of stack entries to be copied is
multiplied by the StackCost to determine the total cost.

If not specified, this will be pulled from the variable "stackcost"
in the config file.  If that can't be found, a default value of 1 is
used.


=item ThreadCost

This is a fixed number of tokens the critter pays for spawning a new
thread.  When a new thread is created, this cost is incurred, plus the
cost of duplicating all of the thread's stacks (see StackCost, above).
The new threads will begin incurring additional costs from the
IterCost (also above), when it begins executing commands of its own.

If not specified, this will be pulled from the variable "threadcost"
in the config file.  If that can't be found, a default value of 10 is
used.


=item Color

This determines the color of the player, which (for board games)
indicates which type of piece the current player is able to play.  It
has no other effect, and thus, it is not necessary for non-boardgame
physics models.

If not specified, a default value of 1 is used.


=item BoardSize

If specified, a board game of the given size (specified as a Vector
object) is created.

=back

=cut

sub new {
    my $package = shift;
    my %args = (
        # defaults
        Color       => 1,
        @_
    );
    # args
    my $usage = 
      "Usage: $package->new(Blueprint => \$blueprint, Physics => \$physics,\n"
     ."                     Tokens => 2000, BoardSize => \$vector, Config => \$config)";
    croak $usage unless exists  $args{Config};
    $args{Tokens}     = $args{Config}->config('tokens'     , 2000) unless defined $args{Tokens};
    $args{CodeCost}   = $args{Config}->config("code_cost"  , 1   ) unless defined $args{CodeCost};
    $args{IterCost}   = $args{Config}->config("iter_cost"  , 2   ) unless defined $args{IterCost};
    $args{RepeatCost} = $args{Config}->config("repeat_cost", 1   ) unless defined $args{RepeatCost};
    $args{StackCost}  = $args{Config}->config("stack_cost" , 1   ) unless defined $args{StackCost};
    $args{ThreadCost} = $args{Config}->config("thread_cost", 10  ) unless defined $args{ThreadCost};

    croak $usage unless exists  $args{Blueprint};
    croak $usage unless exists  $args{Physics};
    croak $usage unless defined $args{Color};

    my $codelen = 1;
    foreach my $d ($args{Blueprint}->size->get_all_components) {
        $codelen *= $d;
    }
    croak "CodeCost must be greater than 0!"   unless $args{CodeCost}   > 0;
    croak "IterCost must be greater than 0!"   unless $args{IterCost}   > 0;
    croak "RepeatCost must be greater than 0!" unless $args{RepeatCost} > 0;
    croak "StackCost must be greater than 0!"  unless $args{StackCost}  > 0;
    croak "ThreadCost must be greater than 0!" unless $args{ThreadCost} > 0;
    $args{Tokens} -= ($codelen * $args{CodeCost});
    croak "Tokens must exceed the code size!"  unless $args{Tokens}     > 0;
    croak "Code must be freeform!  (no newlines)"
        if $args{Blueprint}->code =~ /\n/;

    my $self = bless({}, $package);
    $$self{blueprint}  = $args{Blueprint};
    $$self{boardsize}  = $args{BoardSize} if exists $args{BoardSize};
    $$self{code}       = $$self{blueprint}->code;
    $$self{codecost}   = $args{CodeCost};
    $$self{codesize}   = $$self{blueprint}->size;
    $$self{config}     = $args{Config};
    $$self{dims}       = $$self{codesize}->get_dims();
    $$self{itercost}   = $args{IterCost};
    $$self{repeatcost} = $args{RepeatCost};
    $$self{stackcost}  = $args{StackCost};
    $$self{threadcost} = $args{ThreadCost};
    $$self{tokens}     = $args{Tokens};
    if(exists($$self{boardsize})) {
        $$self{dims} = $$self{boardsize}->get_dims()
            if($$self{dims} < $$self{boardsize}->get_dims());
    }
    if($$self{codesize}->get_dims() < $$self{dims}) {
        # upgrade codesize (keep it hypercubical)
        $$self{codesize} = Language::Befunge::Vector->new(
            $$self{codesize}->get_all_components(),
            map { $$self{codesize}->get_component(0) }
                (1..$$self{dims}-$$self{codesize}->get_dims())
        );

lib/AI/Evolve/Befunge/Critter.pm  view on Meta::CPAN

    $$storage{minsize} = $$self{minsize};
    # store a copy of the Critter in the storage, so _expand (below) can adjust
    # the remaining tokens.
    $$storage{_ai_critter} = $self;
    weaken($$storage{_ai_critter});
    # store a copy of the Critter in the interp, so various command callbacks
    # (below) can adjust the remaining tokens.
    $$interp{_ai_critter} = $self;
    weaken($$interp{_ai_critter});

    $interp->get_ops->{'{'} = \&AI::Evolve::Befunge::Critter::_block_open;
    $interp->get_ops->{'j'} = \&AI::Evolve::Befunge::Critter::_op_flow_jump_to_wrap;
    $interp->get_ops->{'k'} = \&AI::Evolve::Befunge::Critter::_op_flow_repeat_wrap;
    $interp->get_ops->{'t'} = \&AI::Evolve::Befunge::Critter::_op_spawn_ip_wrap;

    my @invalid_meths = (',','.','&','~','i','o','=','(',')',map { chr } (ord('A')..ord('Z')));
    $$self{interp}{ops}{$_} = $$self{interp}{ops}{r} foreach @invalid_meths;

    if(exists($args{Commands})) {
        foreach my $command (sort keys %{$args{Commands}}) {
            my $cb = $args{Commands}{$command};
            $$self{interp}{ops}{$command} = $cb;
        }
    }


    my @params;
    my @vectors;
    push(@vectors, $$self{boardsize}) if exists $$self{boardsize};
    push(@vectors, $$self{maxsize}, $$self{codesize});
    foreach my $vec (@vectors) {
        push(@params, $vec->get_all_components());
        push(@params, 1) for($vec->get_dims()+1..$$self{dims});
    }
    push(@params, $$self{threadcost}, $$self{stackcost}, $$self{repeatcost}, 
         $$self{itercost}, $$self{tokens}, $$self{dims});
    push(@params, $self->physics->token) if defined $self->physics->token;

    $$self{interp}->set_params([@params]);

    return $self;
}


=head1 METHODS

=head2 invoke

    my $rv = $critter->invoke($board);
    my $rv = $critter->invoke();

Run through a life cycle.  If a board is specified, the board state
is copied into the appropriate place before execution begins.

This should be run within an "eval"; if the critter causes an
exception, it will kill this function.  It is commonly invoked by
L</move> (see below), which handles exceptions properly.

=cut

sub invoke {
    my ($self, $board) = @_;
    delete($$self{move});
    $self->populate($board) if defined $board;
    my $rv = Result->new(name => $self->blueprint->name);
    my $initial_ip = Language::Befunge::IP->new($$self{dims});
    $initial_ip->set_position($$self{codeoffset});
    my $interp = $self->interp;
    push(@{$initial_ip->get_toss}, @{$interp->get_params});
    $interp->set_ips([$initial_ip]);
    while($self->tokens > 0) {
        my $ip = shift @{$interp->get_ips()};
        unless(defined($ip)) {
            my @ips = @{$interp->get_newips};
            last unless scalar @ips;
            $ip = shift @ips;
            $interp->set_ips([@ips]);
        }
        unless(defined $$ip{_ai_critter}) {
            $$ip{_ai_critter} = $self;
            weaken($$ip{_ai_critter});
        }
        last unless $self->spend($self->itercost);
        $interp->set_curip($ip);
        $interp->process_ip();
        if(defined($$self{move})) {
            debug("move made: " . $$self{move} . "\n");
            $rv->choice( $$self{move} );
            return $rv;
        }
    }
    debug("play timeout\n");
    return $rv;
}


=head2 move

    my $rv = $critter->move($board, $score);

Similar to invoke(), above.  This function wraps invoke() in an
eval block, updates a scoreboard afterwards, and creates a "dead"
return value if the eval failed.

=cut

sub move {
    my ($self, $board) = @_;
    my $rv;
    local $@ = '';
    eval {
        $rv = $self->invoke($board);
    };
    if($@ ne '') {
        debug("eval error $@\n");
        $rv = Result->new(name => $self->blueprint->name, died => 1);
        my $reason = $@;
        chomp $reason;
        $rv->fate($reason);
    }
    $rv->tokens($self->tokens);
    return $rv;
}


=head2 populate

    $critter->populate($board);

Writes the board game state into the Befunge universe.

=cut

sub populate {
    my ($self, $board) = @_;
    my $storage = $$self{interp}->get_storage;
    $storage->store($board->as_string);
    $$self{interp}{_ai_board} = $board;
    weaken($$self{interp}{_ai_board});
}


=head2 spend

    return unless $critter->spend($tokens * $cost);

Attempts to spend a certain amount of the critter's tokens.  Returns
true on success, false on failure.

=cut

sub spend {
    my ($self, $cost) = @_;
    $cost = int($cost);
    my $tokens = $self->tokens - $cost;
    #debug("spend: cost=$cost resulting tokens=$tokens\n");
    return 0 if $tokens < 0;
    $self->tokens($tokens);
    return 1;
}


# sandboxing stuff
{
    no warnings 'redefine';

    # override Storage->expand() to impose bounds checking
    my $_lbsgv_expand;
    BEGIN { $_lbsgv_expand = \&Language::Befunge::Storage::Generic::Vec::expand; };
    sub _expand {
        my ($storage, $v) = @_;
        if(exists($$storage{maxsize})) {
            my $min = $$storage{minsize};
            my $max = $$storage{maxsize};
            die "$v is out of bounds [$min,$max]!\n"
                unless $v->bounds_check($min, $max);
        }
        my $rv = &$_lbsgv_expand(@_);
        return $rv;
    }
    # redundant assignment avoids a "possible typo" warning
    *Language::Befunge::Storage::Generic::Vec::XS::expand = \&_expand;
    *Language::Befunge::Storage::Generic::Vec::XS::expand = \&_expand;
    *Language::Befunge::Storage::Generic::Vec::expand     = \&_expand;

    # override IP->spush() to impose stack size checking
    my $_lbip_spush;
    BEGIN { $_lbip_spush = \&Language::Befunge::IP::spush; };
    sub _spush {
        my ($ip, @newvals) = @_;
        my $critter = $$ip{_ai_critter};
        return $ip->dir_reverse unless $critter->spend($critter->stackcost * scalar @newvals);
        my $rv = &$_lbip_spush(@_);
        return $rv;
    }
    *Language::Befunge::IP::spush = \&_spush;

    # override IP->ss_create() to impose stack count checking
    sub _block_open {
        my ($interp) = @_;
        my $ip       = $interp->get_curip;
        my $critter = $$ip{_ai_critter};
        my $count    = $ip->svalue(1);
        return $ip->dir_reverse unless $critter->spend($critter->stackcost * $count);
        return Language::Befunge::Ops::block_open(@_);
    }

    # override op_flow_jump_to to impose skip count checking
    sub _op_flow_jump_to_wrap {
        my ($interp) = @_;
        my $ip       = $interp->get_curip;
        my $critter  = $$interp{_ai_critter};
        my $count    = $ip->svalue(1);
        return $ip->dir_reverse unless $critter->spend($critter->repeatcost * abs($count));
        return Language::Befunge::Ops::flow_jump_to(@_);
    }

    # override op_flow_repeat to impose loop count checking
    sub _op_flow_repeat_wrap {
        my ($interp) = @_;
        my $ip       = $interp->get_curip;
        my $critter  = $$interp{_ai_critter};
        my $count    = $ip->svalue(1);
        return $ip->dir_reverse unless $critter->spend($critter->repeatcost * abs($count));
        return Language::Befunge::Ops::flow_repeat(@_);
    }

    # override op_spawn_ip to impose thread count checking
    sub _op_spawn_ip_wrap {
        my ($interp) = @_;
        my $ip       = $interp->get_curip;
        my $critter  = $$interp{_ai_critter};
        my $cost     = 0;$critter->threadcost;
        foreach my $stack ($ip->get_toss(), @{$ip->get_ss}) {
            $cost   += scalar @$stack;
        }
        $cost       *= $critter->stackcost;
        $cost       += $critter->threadcost;
        return $ip->dir_reverse unless $critter->spend($cost);
        # This is a hack; Storable can't deep copy our data structure.
        # It will get re-added to both parent and child, next time around.
        delete($$ip{_ai_critter});
        return Language::Befunge::Ops::spawn_ip(@_);
    }
}

1;