Re: Checking parameters

["Lennart Borgman (gmail)" <lennart.borgman@gmail.com>]

Lennart Borgman (gmail) wrote:
> You probably want to use the most simple way, something like
> 
> (defun get-hours(time)
>   (interactive "sHH:MM: ")
>   (let ((timelist (split-string time ":"))
>         (errmsg "Time format error"))
>     (unless (= (length (nth 1 timelist)) 2)
>       (error errmsg))
>     (+
>       (string-to-number (nth 0 timelist))
>       (/
>         (string-to-number (nth 1 timelist))
>         60.0))))

And this is better:

(defun get-hours(time)
   (interactive "sHH:MM: ")
   (let ((timelist (split-string time ":"))
         (errmsg "Time format error"))
     (save-match-data
       (unless (string-match "\\`[0-9]+:[0-9]\\{2\\}\\'" time)
         (error errmsg)))
     (+
      (string-to-number (nth 0 timelist))
      (/
       (string-to-number (nth 1 timelist))
       60.0))))