presto-main/src/main/java/io/prestosql/sql/planner/ExpressionExtractor.java/Visitor/Visitor
class Visitor:        Visitor(Consumer<Expression> consumer, boolean recursive, Lookup lookup)
        {
            this.consumer = requireNonNull(consumer, "consumer is null");
            this.recursive = recursive;
            this.lookup = requireNonNull(lookup, "lookup is null");
        }