public interface Query extends Serializable
A query is abstractly represented by a composite made of implementations of this interface. The syntax can be different from parser to parser, but the result of the parsing process is an instance of this class.
To this purpose, the implementation of
on internal nodes must gather in an array (or in an element)
the results returned by the recursive calls to
on subnodes and pass the array (or the element) to the suitable
Since allocating a generic array is impossible, every visitor must provide an explicit
method which returns an array of the correct type.