You're saying I should use custom symbols like 'true and 'false and put in checks like (eq 'false x) instead of (null x)? To avoid subtle errors? Honest question.
Postmodern (https://quickref.common-lisp.net/postmodern.htm), a library to interface with Postresql will use the keyword `:null` to represent null, and T and nil to represent boolean true and false.
