replaceall regex does not produce result for control characters in trino CLI

[natarajank11]

Trino UDF (version 407):
Basically i want to remove control characters from the string.

I tried following regex pattern,
String regex = "[\\\\p{C}]";

Trino result,
select rm_code('hello\bhello\thello'); => hellobhellothello

This ticket is similar to #17474

[hashhar]

SQL varchar literals don't have control characters so your regex will never match.

The \b is treated literally as \b -> SELECT 'hello\bworld'; -- hello\bworld

So you need to change your regex to: String regex = "\\\\b"; to match the \b in varchar literals.

BTW since SQL varchar literals don't have any control characters why do you want to "remove control characters" and how do you plan to differentiate between hello\world and hello\wworld (i.e. a case where the \ is a literal slash and not part of an escape).