Research on ?? operators

Hello generals,

I'm trying to resurrect a change to the PHP PDO driver to allow using
the "?" json operator (and other operators containing a question mark),
without it being interpreted as a placeholder for a query argument. In
order to do so, like Hibernate, I went for the double "??" escaping:

https://wiki.php.net/rfc/pdo_escape_placeholders

One question that I'm supposed to answer now is: is there any known
usage in the wild of some custom "??" operator that would require funny
escaping like "????"?

I've tried to search pgxn but couldn't find any match, so I thought it
was worth to try and ask here.


Cheers
-- 
Matteo Beccati

Development & Consulting - http://www.beccati.com/