/**
 * Binary search tree implementation in JavaScript.
 * Requires JS.Class - http://jsclass.jcoglan.com/
 *
 * Performs naïve comparison using operators; a good extension would be support
 * for JS.Class's Comparable module.
 */
var BinaryTree = new JS.Class({
  initialize: function(left, value, right) {
    this.value = value;
    this.left  = left;
    this.right = right;
  },
  
  isEmpty: function() {
    return !this.value;
  },
  
  insert: function(x) {
    if (this.isEmpty()) {      
      this.value = x;
    } else if (x < this.value) {
      (this.left)
        ? this.left.insert(x)
        : this.left = new BinaryTree(null, x, null);
    } else if (x > this.value) {
      (this.right)
        ? this.right.insert(x)
        : this.right = new BinaryTree(null, x, null);
    }
  },
  
  isMember: function(x) {
    if (this.isEmpty()) {
      return false;      
    } else if (x < this.value) {      
      return !!this.left && this.left.isMember(x);
    } else if (x > this.value) {      
      return !!this.right && this.right.isMember(x);
    } else {      
      return true;
    }
  }
});