code: function () {
      var pattern = /\{(\d+)\}/g;
      //safer way to convert a pseudo array to an object array
      var args = Array.prototype.slice.call(arguments);
      var s = args.shift();
      return s.replace(pattern, function(c, d) {
        var replacement = args[d] ;
        if (lib.isNull(replacement)) {
          replacement = "";
        }
        return replacement;
      });
    }
docs: return a string formatted with the passed arguments
  @example
  
  var s = $a.format('Some {0} with a {1} mood {2}', 'String', 'good', 'arrived');
  //output
  //s = 'Some String with a good mood arrived'