(defmacro fbind (bindings &body body) (let ((bindings (mapcar (lambda (b) (list (first b) (second b) (gensym))) bindings))) (eval `(alexandria:once-only ,(mapcar (lambda (b) `(,(third b) ',(second b))) bindings) ;; dance around with BINDINGS since we're doubly quoted `(flet ,(list ,@(mapcar (lambda (b) ``(,',(first b) (&rest args) (apply ,,(third b) args))) bindings)) ;; dance around with BODY since we're doubly quoted ,@(list ,@(mapcar (lambda (f) `',f) body))))))) (let ((counter 0)) (flet ((get-function (x) (lambda (a) (+ a x)))) (format t "counter before: ~a~%" counter) (fbind ((fun1 (progn (incf counter) (get-function 5))) (fun2 (get-function 10))) (format t "counter after: ~a~%" counter) (prog1 (list (fun1 5) (fun1 5) (fun2 10) (fun2 10)) (format t "counter way after: ~a~%" counter))))) ;; > counter before: 0 ;; > counter after: 1 ;; > counter way after: 1 ;; => (10 10 20 20)