[plainto_tsquery] using OR

Hi everybody,

I struggle to find a clean solution in an application to safely parse
the query input string of a user.

Currently, I am inclined to split the string with some magic regex and
build it safely together using ' | '. That solution, however, is
error-prone and hides the powerful features of tsquery that PostgreSQL
could provide from the user.

Is there a way to safely create a tsquery out of user's input?
Optionally, when the user types '&', '|', '!' '(' and ')' it could be
interpreted like typical tsquery syntax BUT still creates valid tsquery.

Regards,

--
Sven R. Kunze
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