presto-parser/src/main/java/io/prestosql/sql/ExpressionFormatter.java/ExpressionFormatter/joinExpressions
class ExpressionFormatter:        private String joinExpressions(List<Expression> expressions)
        {
            return Joiner.on(", ").join(expressions.stream()
                    .map((e) -> process(e, null))
                    .iterator());
        }