; Invoke the published macro's closure as an ordinary function, then evaluate
; its returned expansion. This bypasses the host's canonical backquote path.
(`(a ,(car '(b c)))
 (expand ((caddr bquote) '(a (comma (car '(b c)))))) (a b))
(`(head . ,@'(tail))
 (expand ((caddr bquote) '(head comma-at '(tail)))) (head . tail))
(`(,@'(a b) . ,@'(tail))
 (expand ((caddr bquote) '((comma-at '(a b)) comma-at '(tail)))) (a b . tail))
(`(,(do (set marker 'head) 'a) . ,@(do (set marker 'tail) '(z)))
 (expand ((caddr bquote) '((comma (do (set marker 'head) 'a)) comma-at (do (set marker 'tail) '(z))))) (a . z))
(marker (source marker) tail)
(`(,@xs ,(do (xar xs 'changed) 'last))
 (expand ((caddr bquote) '((comma-at xs) (comma (do (xar xs 'changed) 'last))))) (changed b last))
(xs (source xs) (changed b))