1-2 of about 2 matches for site:www.gnu.org primary datum
https://www.gnu.org/software/guile/manual/html_node/Syntax-Case.html
only if it is an identifier. This is impossible with syntax-rules , given the datum matching forms. But with
http://www.gnu.org/software/clisp/impnotes.html
SLOT-MAKUNBOUND , SLOT-EXISTS-P , CALL-NEXT-METHOD , NEXT-METHOD-P , NO-APPLICABLE-METHOD , CLOS:NO-PRIMARY-METHOD , NO-NEXT-METHOD