A simple smilies parser class for MooTools, broken

gistfile1.js

var SmiliesParser = new Class({
  initialize: function(smiledata) {
    this.data = smiledata;
    this.sensor = new RegExp($H(smiledata).getValues().map(function(item) {
      return item.map(function(i) {
        return '(' + i.escapeRegExp() + ')';
      }).join('|');
    }).join('|'), 'g');
  },
  
  applyToTextNode: function(startNode) {
    var smiles = []; var self = this;
    var result; var node = startNode;
    
    while (result = this.sensor.exec(node.data)) {
      console.log(node.data);
      var newNode = node.splitText(result.index);
      node = newNode.splitText(result[0].length);
      smiles.push(newNode);
    }
    
    if (smiles.length > 0) console.log(JSON.encode(smiles.map(function(i) {return i.data;})));
    
    smiles.each(function(smile) {
      var src;
      
      
      Hash.getKeys(self.data).each(function(smileImg) {
        self.data[smileImg].each(function(test) {
          if (smile.data == test) src = smileImg;
        });
      });
      
      var img = new Element('img', {alt: smile.data, title: smile.data, src: src});
      smile.parentNode.replaceChild(img, smile);
    });
    
  },
  
  applyToElement: function(element) {
    var self = this;
    $A($(element).childNodes).each(function(node) {
      switch (node.nodeType) {
      case Node.TEXT_NODE:
        self.applyToTextNode(node);
        break;
      case Node.ELEMENT_NODE:
        self.apply(node);
        break;
      }  
    });
  }
});


//...

window.addEvent('domready', function() {
  window.smilies = new SmiliesParser(smiliesData);
});

//... later ...
smilies.applyToElement(someElement);
// logs 'window' as the 'this' object and raises an error about applyToTextNode not being in the window object and not being a function.