* [attribute value](http://dev.w3.org/csswg/selectors4/#attribute-selectors): `[attr="foo"]` or `[attr=123]`
* attribute regex: `[attr=/foo.*/]` or (with flags) `[attr=/foo.*/is]`
* attribute conditions: `[attr!="foo"]`, `[attr>2]`, `[attr<3]`, `[attr>=2]`, or `[attr<=3]`
* nested attribute: `[attr.level2="foo"]`
* field: `FunctionDeclaration > Identifier.id`
* [First](http://dev.w3.org/csswg/selectors4/#the-first-child-pseudo) or [last](http://dev.w3.org/csswg/selectors4/#the-last-child-pseudo) child: `:first-child` or `:last-child`
* [nth-child](http://dev.w3.org/csswg/selectors4/#the-nth-child-pseudo) (no ax+b support): `:nth-child(2)`
* [nth-last-child](http://dev.w3.org/csswg/selectors4/#the-nth-last-child-pseudo) (no ax+b support): `:nth-last-child(1)`