match(Node node). This method should return
trueif a node is matched. You may also override the method
getPseudoClassName()if you don't want to generate a pseudo-class name from the class name. For example:
PseudoFunctionclass. Additionally, you need to also implement a method that parses input expression. This expression is later passed to the matching method.
:len-fn(3)to match all nodes with short names:)