text: /**
   * Return the set theoretical union of this and *that*.
   * @arguments _(that)_
   * @example
   *  [1, 2, 3].union([2, 3, 4, 5]); // => [ 1, 2, 3, 4, 5 ]
   */
  sc.define("union", {
    Array: function(that) {
      var result = this.slice(), i, imax;
      for (i = 0, imax = that.length; i < imax; ++i) {
        if (result.indexOf(that[i]) === -1) {
          result.push(that[i]);
        }
      }
      return result;
    }
  });
  