Re: A macro and an unwanted containing list in the resulting form

[Juanma Barranquero]

On 5/23/07, Sebastian Tennant <sebyte@smolny.plus.com> wrote:


>   (cond (((equal e "hello") (message "hi"))
>         ^((equal e "goodbye") (message "bye"))))
>         |                                     ^
>         |                                     |
>         +--------- unwanted list -------------+
>
> Clearly my approach is wrong (because this is how mapcar behaves), so
> what is the best way to go about this?

Try with

 (defmacro build-cond (alist)
   (append '(cond)
           (mapcar '(lambda (each)
                     (cons (list 'equal 'my-var (car each)) (list (cdr each))))
                   alist)))

Is there any reason to make the argument of build-cond an alist? You could try

(defmacro build-cond (&rest conds)
 (append '(cond)
         (mapcar '(lambda (each)
                   (cons (list 'equal 'my-var (car each)) (list (cdr each))))
                 conds)))

and then use

 (build-cond ("hello" . (message "hi"))
             ("goodbye" . (message "bye"))

            Juanma