docs: function(condition, successTempl, failTempl) {
  		successTempl = (typeof successTempl === 'string') ? y().use(successTempl) : successTempl;
  		if (failTempl)
  			failTempl = (typeof failTempl === 'string') ? y().use(failTempl) : failTempl;
  		return this.exec('if', [interpolable(condition), successTempl, failTempl]);
  	}