code: function(following) {
          if (following.emitter != this.emitter) {
              throw new Error('Can\'t merge Arguments from different EventEmitters');
          }
          return new Argument(
              this.emitter,
              this.text + this.suffix + following.prefix + following.text,
              this.start, following.end,
              this.prefix,
              following.suffix);
      }
docs: Return the result of merging these arguments.
  TODO: What happens when we're merging arguments for the single string
  case and some of the arguments are in quotation marks?