presto-main/src/main/java/io/prestosql/sql/relational/SqlToRowExpressionTranslator.java/Visitor/visitExpression
class Visitor:        @Override
        protected RowExpression visitExpression(Expression node, Void context)
        {
            throw new UnsupportedOperationException("not yet implemented: expression translator for " + node.getClass().getName());
        }