Solution to level 6 in Untrusted: http://alex.nisnevich.com/untrusted/

untrusted-lvl6-solution.js

/****************
 * drones101.js *
 ****************
 *
 * Do you remember, my dear Professor, a certain introductory
 * computational rationality class you taught long ago? Assignment
 * #2, behavior functions of autonomous agents? I remember that one
 * fondly - but attack drones are so much easier to reason about
 * when they're not staring you in the face, I would imagine!
 */

function startLevel(map) {
    function moveToward(obj, type) {
        var target = obj.findNearest(type);
        var leftDist = obj.getX() - target.x;
        var upDist = obj.getY() - target.y;

        var direction;
        if (upDist == 0 && leftDist == 0) {
            return;
        } if (upDist > 0 && upDist >= leftDist) {
            direction = 'up';
        } else if (upDist < 0 && upDist < leftDist) {
            direction = 'down';
        } else if (leftDist > 0 && leftDist >= upDist) {
            direction = 'left';
        } else {
            direction = 'right';
        }

        if (obj.canMove(direction)) {
            obj.move(direction);
        }
    }

    map.defineObject('attackDrone', {
        'type': 'dynamic',
        'symbol': 'd',
        'color': 'red',
        'onCollision': function (player) {
            player.killedBy('an attack drone');
        },
        'behavior': function (me) {
            moveToward(me, 'player');
        }
    });


    map.placePlayer(1, 1);
    map.placeObject(map.getWidth()-2, 12, 'attackDrone');
    map.placeObject(map.getWidth()-1, 12, 'exit');

    map.placeObject(map.getWidth()-1, 11, 'block');
    map.placeObject(map.getWidth()-2, 11, 'block');
    map.placeObject(map.getWidth()-1, 13, 'block');
    map.placeObject(map.getWidth()-2, 13, 'block');
    map.placeObject(map.getWidth()-4, 12, 'block');
    map.placeObject(map.getWidth()-4, 13, 'block');
    map.placeObject(map.getWidth()-4, 14, 'block');
    
    map.placeObject(map.getWidth()-5, 14, 'block');
    map.placeObject(map.getWidth()-5, 16, 'block');
    
    map.placeObject(map.getWidth()-6, 14, 'block');
    map.placeObject(map.getWidth()-6, 16, 'block');
    
    map.placeObject(map.getWidth()-7, 14, 'block');
    map.placeObject(map.getWidth()-8, 14, 'block');
    
    //mur vertical
    map.placeObject(map.getWidth()-8, 15, 'block');
    map.placeObject(map.getWidth()-8, 16, 'block');
    map.placeObject(map.getWidth()-8, 17, 'block');
    
    //mur horizontal
    map.placeObject(map.getWidth()-9, 16, 'block');
    map.placeObject(map.getWidth()-10, 16, 'block');
    map.placeObject(map.getWidth()-11, 16, 'block');
    map.placeObject(map.getWidth()-12, 16, 'block');
    map.placeObject(map.getWidth()-13, 16, 'block');
    map.placeObject(map.getWidth()-14, 16, 'block');
    map.placeObject(map.getWidth()-15, 16, 'block');
    map.placeObject(map.getWidth()-16, 16, 'block');
    map.placeObject(map.getWidth()-17, 16, 'block');
    map.placeObject(map.getWidth()-18, 16, 'block');
    map.placeObject(map.getWidth()-19, 16, 'block');
    map.placeObject(map.getWidth()-20, 16, 'block');
    map.placeObject(map.getWidth()-21, 16, 'block');
    map.placeObject(map.getWidth()-22, 16, 'block');
    map.placeObject(map.getWidth()-23, 16, 'block');
    map.placeObject(map.getWidth()-24, 16, 'block');
    map.placeObject(map.getWidth()-25, 16, 'block');
    map.placeObject(map.getWidth()-26, 16, 'block');
    map.placeObject(map.getWidth()-27, 16, 'block');
    map.placeObject(map.getWidth()-28, 16, 'block');
    map.placeObject(map.getWidth()-29, 16, 'block');
    //
    map.placeObject(map.getWidth()-30, 16, 'block');
    map.placeObject(map.getWidth()-31, 16, 'block');
    map.placeObject(map.getWidth()-32, 16, 'block');
    map.placeObject(map.getWidth()-33, 16, 'block');
    map.placeObject(map.getWidth()-34, 16, 'block');
    map.placeObject(map.getWidth()-35, 16, 'block');
    map.placeObject(map.getWidth()-36, 16, 'block');
    map.placeObject(map.getWidth()-37, 16, 'block');
    map.placeObject(map.getWidth()-38, 16, 'block');
    map.placeObject(map.getWidth()-39, 16, 'block');
    map.placeObject(map.getWidth()-40, 16, 'block');
    map.placeObject(map.getWidth()-41, 16, 'block');
    map.placeObject(map.getWidth()-42, 16, 'block');
    map.placeObject(map.getWidth()-43, 16, 'block');
    map.placeObject(map.getWidth()-44, 16, 'block');
    
    map.placeObject(map.getWidth()-44, 17, 'block');
    map.placeObject(map.getWidth()-44, 18, 'block');
    map.placeObject(map.getWidth()-44, 19, 'block');
    map.placeObject(map.getWidth()-44, 20, 'block');
    map.placeObject(map.getWidth()-44, 21, 'block');
    map.placeObject(map.getWidth()-44, 22, 'block');
    map.placeObject(map.getWidth()-44, 23, 'block');
    map.placeObject(map.getWidth()-44, 24, 'block');
    map.placeObject(map.getWidth()-44, 25, 'block');
    map.placeObject(map.getWidth()-44, 26, 'block');
    
    
    
    
    map.placeObject(map.getWidth()-4, 16, 'block');
    map.placeObject(map.getWidth()-3, 16, 'block');
    map.placeObject(map.getWidth()-2, 16, 'block');
    map.placeObject(map.getWidth()-1, 16, 'block');
    
    //map.placeObject(map.getWidth()-4, 15, 'block');
    //map.placeObject(map.getWidth()-4, 16, 'block');
    
    
}

function validateLevel(map) {
    map.validateExactlyXManyObjects(1, 'exit');
}