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.defineObject('friendlyDrone', {
        'type': 'dynamic',
        'symbol': 'd',
        'color': 'lime',
        'behavior': function (me) {
            moveToward(me, 'attackDrone');
        }
    });
    map.placeObject(map.getWidth()-1, 0, 'friendlyDrone');
    map.placeObject(map.getWidth()-1, map.getHeight()-1, 'friendlyDrone');
    map.placeObject(0, 0, 'friendlyDrone');
    map.placeObject(0, map.getHeight()-1, 'friendlyDrone');
    /*
    This is certainly not the shortest solution, of course
    and likely not be expected one, either. However,
    as in any other art (and make no mistake, coding is an art) 
    it's fun to use your opponent's code against them ;-)
    Twisted Code (sometimes called macks2008 or macks2010) was here
    */


}

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

Not to oversimplify: while coding is no doubt an art in my humble opinion (there are many solutions that achieve the same or extremely similar goals, for instance), it also has its foundations in science.

in fact... most arts have their foundation in science in some way or another. We discovered paint by smashing things together, and analyzing the result of smashing things (e.g. "fascinating, if I grind this rock against this surface, it makes the surface brown"). Perhaps programming just developed much faster because we had robots to make all the "Paint" (semiconductor chips) and people like Alan Turing had too much free time on their hands?