It creates a Lisp stub with the same signature whose body simply throws

an error telling you that you tried to call a PS function from Lisp. Why is that

useful? Because now your PS functions are fully integrated with Slime.

You can jump around with M-., get arglist info in the minibuffer, and so on.

After a week of using this, I can't believe how much of a difference it makes.

In PS, DEFUN-JS translates trivially to DEFUN. Of course you still need a

way to collect the JS emitted by all these forms, but PS is agnostic on how

that should be done.

A side note: we also converted nearly all our ps macros to DEFMACRO+PS

forms at the toplevel. This has the neat property that you can now

look at expansions using the highly convenient Slime macroexpand. I doubt

that this is a perfect solution (no doubt you can trip yourself up on differences

between the CL and PS macro environments), but it's sure handier than calling

PS::PS-MACROEXPAND from the REPL.

Daniel

p.s. The following has been stripped of a couple of functions specific to

our project. I tested it a bit, but if I missed anything, let me know.

(defmacro defun-js (name lambda-list &body body)

(declare (ignore body))

(labels ((sym% (argspec) (if (symbolp argspec) argspec (car argspec))))

(multiple-value-bind (required optionals restp rest keyp keys allowp auxp aux morep more-context more-count beyond-requireds? key-object)

(ps::parse-lambda-list lambda-list)

(declare (ignore restp keyp allowp auxp aux morep more-context more-count beyond-requireds? key-object))

;; get rid of init forms, which can't be evaluated in Lisp.

(setf optionals (mapcar #'sym% optionals) keys (mapcar #'sym% keys))

`(defun ,name (,@required ,@(when optionals `(&optional ,@optionals))

,@(when rest `(&rest ,rest)) ,@(when keys `(&key ,@keys)))

(declare (ignore ,@required ,@optionals ,@(when rest (list rest)) ,@keys))

(error "The ~s function is js-only and cannot be called from Lisp." ',name)))))

(defpsmacro defun-js (name lambda-list &body body)

`(defun ,name ,lambda-list ,@body))