bug#58532: 29.0.50; Support displaying imenu entries in a separate buffer

["Daniel Martín via Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Juri Linkov <juri@linkov.net> writes:

>
> Unfortunately, mupdf/mutool doesn't support Unicode characters:
> https://bugs.ghostscript.com/show_bug.cgi?id=702358
> Maybe doc-view--pdf-outline could post-process the output
> to replace hex-encoded numbers with their character equivalents?
>

Do you mean for old versions of mupdf?  IIUC, recent versions of mupdf
already do the right thing: They decode the runes (Unicode codepoints)
from the byte string and encode them in UTF-8, verbatim.  Only control
characters are hex-encoded.  I've opened in Emacs the PDF attached to
the mupdf bug report and it displays the outline correctly (mutool
version 1.19.0).

>
> The problem is that imenu-submenus-on-top is t by default,
> but such order is incompatible with the outline-mode trees.
> For example, all functions belong to the Variables outline:
>
> * Types
>   imenu
>   imenu-unavailable
> * Variables
>   imenu-after-jump-hook
>   imenu-auto-rescan
>   imenu-auto-rescan-maxout
>   ...
> imenu
> imenu--cleanup
> imenu--completion-buffer
> imenu--create-keymap
> ...

That's a good point.  Perhaps we need to create a special mode to
display the imenu hierarchy.