I am trying to continue on the quest I described before -- "I want to create a variant of `defun' that takes arguments from Emacs and assembles a body to be evaluated by SLIME." I think I am most of the way there. Dan McCarthy pointed out: You probably want to quote the argument to slime-eval; that error is b/c the (progn...) is being evaluated in Emacs, not CL. Oops -- yes that I should be sure SLIME is doing the evalution, not Emacs -- but note, I also need to make sure that in the data I am sending to SLIME contains the values of the arguments, not just their names! Here is a macro that accomplishes this: (defmacro lefun (name arglist &rest body) `(defun ,name ,arglist (slime-eval (list (append (list 'lambda ',arglist) ',body) ,@arglist)))) Unfortunately, it still produces an error when I test it with the following code: (lefun myplus (a b) (+ a b)) (myplus 2 3) Specifically, the above triggers SLDB with the following message: Execution of a form compiled with errors. Form: ((LAMBDA (A B) (+ A B)) 2 3) Compile-time error: illegal function call I do not know what this means. It seems there is a work-around using Vladimir's suggestion on how to interact programmatically with the REPL: (defmacro lefun (name arglist &rest body) `(defun ,name ,arglist (setq argument-values (list )) (second (slime-eval (list 'swank:eval-and-grab-output (format "%S" (list (append (list 'lambda ',arglist) ',body) ,@arglist))))))) Testing: (lefun current-package () *package*) (current-package) (lefun elephant-toy () (elephant::open-store '(:bdb "/home/joe/musndb")) (elephant::add-to-root "foo" 2) (elephant::close-store)) (elephant-toy) In conclusion, I seem to have tentatively solved the problem -- but I would appreciate it if someone could explain why I am seeing the error mentioned above!