bug#64516: [PATCH] docview: Only enable imenu when supported

[Tassilo Horn]

Hi Morgan,

my reasoning was to have an explanation in the *Messages* buffer for people who 
ask themselves "where the heck is the Outline menu item"? If it's done by 
condition-case or with-demoted-errors doesn't really matter. Feel free to adapt 
it to your preference.

Thanks,
Tassilo

16.07.2023 17:03:05 Morgan Smith <Morgan.J.Smith@outlook.com>:

> Hello,
> 
> First of all I'd like to apologize for dragging this out and missing
> some details.  If I paid a little more attention this would likely be
> done by now :P
> 
> Tassilo Horn <tsdh@gnu.org> writes:
> 
>> Why do you ignore the error altogether?
> 
> So we have 3 scenarios: mutool not installed, mutool failed, and mutool
> is successful.
> 
> Your patch would send a message on setup when mutool fails, but would
> not say anything in the other two scenarios.
> 
> My patch would be silent on setup.
> 
> Both patches would give the user an error if they actually try to use
> imenu.
> 
> In my opinion, we should either be completely silent (on setup) or send a 
> message
> when imenu is set up correctly.  If you wanted to send a message when it
> fails I would accept that, but maybe we should consider also sending the
> message when mutool is not installed.
> 
> 
> Also, we have a macro 'with-demoted-errors' but we are missing a
> 'with-demoted-error' macro that lets you specify what error to demote.
> It would be cool if you converted this part of your patch into a
> definition of a 'with-demoted-error' macro.
> 
> 
> --8<---------------cut here---------------start------------->8---
> +    (condition-case imenu-error
> +        (doc-view-imenu-setup)
> +      (imenu-unavailable (message "imenu support unavailable: %s"
> +                                  (cadr imenu-error))))
> --8<---------------cut here---------------end--------------->8---