I'm trying to create a macro (bar) that should be used like this:
(let ((my-var "foo"))
(bar ("some")
:buzz (lambda () (format t "~a~%" my-var))))
The macro should basically just FUNCALL the lambda with taking MY-VAR into account.
What I've come up with is this:
(defmacro bar ((thing) &body body)
`(funcall (coerce (getf (list ,@body) :buzz) 'function)))
This works, it prints "foo". But I'd like to know if this is how this is done or if there is a better way of doing this.
Well, for a start if you don't need the extra, unused argument, then this is just funcall, since (lambda ...) denotes a function.
(let ((my-var "foo"))
(funcall (lambda () (format t "~a~%" my-var))))
So even if you didn't want to call this funcall you could write it as a function, not a macro: it's not doing any code transformation. But presumably you actually do need this extra argument, and you are intending to use it for some purpose in the expansion, so what you need then is a macro which takes keyword arguments and just expands into a suitable funcall form:
(defmacro bar ((thing) &key (buzz '(lambda ())))
(declare (ignore thing))
`(funcall ,buzz))