Re: How to parse a string?

[Greg Hill]

At 11:10 PM +0200 5/1/03, Pascal Bourguignon wrote:
> Francois Fleuret <francois.fleuret@inria.fr> writes:
>  > But is there a generic way to do such a thing ? No scanf equivalent
>  > around ?
> Just encapsulate the line with '( ... ):
>
>     (defun scanf (string) ;; no need to specify the format and the variable,
>        "We return a list of item scanned from the string."
>       (read (concat "( " string " )")))
>
> (dolist (item (scanf "10 20 3.33 wordA wordB wordC"))
>     (show item (type-of item)))
>
> ==> (10 integer)
> ==> (20 integer)
> ==> (3.33 float)
> ==> (wordA symbol)
> ==> (wordB symbol)
> ==> (wordC symbol)


Nice trick, if you want the strings read as symbols.  If you're 
looking for strings, how about:

(defun scanf (string)
  "We return a list of items scanned from the string."
  (mapcar (lambda (x) (if (symbolp x) (symbol-name x) x))
          (read (concat "( " string " )"))))


By the way, where is that "show" function defined?  I presume it is 
effectively:

(defun show (&rest args) (princ "==> ") (princ args) (terpri))

--Greg