Re: with-demoted-errors

[Glenn Morris]

Karl Fogel wrote:

> From: Stefan Monnier <address@hidden>
>>> +                      ;; This is with-demoted-errors, but we want to
>>> +                      ;; mention save-place in any error message.
>>> +                      (condition-case err
>>> +                        (car (read-from-string
>>> +                              (buffer-substring (point-min) (point-max))))
>>> +                        (error (message "Error reading save-place-file: 
>>> %S" err)
>>> +                               nil)))
>> 
>>I remember having similar desires in other places.  Should we add
>>a "format" argument to with-demoted-errors?
>
> I'm not sure I understand the original comment in saveplace.el,
> actually.  Does "mention save-place" mean something special there?
>
> The error string already says "save-place-file", and it will print `err'
> too...  In other words, why couldn't one just use `with-demoted-errors'
> in that spot right now?  Another way to say it is: the BODY argument to
> `with-demoted-errors' can format anything in its error messages that it
> want to, so I don't see why that code in saveplace.el isn't using
> `with-demoted-errors' already.

Because

(with-demoted-errors 
   (car (read-from-string
      (buffer-substring (point-min) (point-max)))))

just prints "end-of-file", which gives you no clue that the error is
coming from save-place.