presto-parser/src/main/java/io/prestosql/sql/ExpressionFormatter.java/ExpressionFormatter/visitCurrentTime
class ExpressionFormatter:        @Override
        protected String visitCurrentTime(CurrentTime node, Void context)
        {
            StringBuilder builder = new StringBuilder();

            builder.append(node.getFunction().getName());

            if (node.getPrecision() != null) {
                builder.append('(')
                        .append(node.getPrecision())
                        .append(')');
            }

            return builder.toString();
        }