bug#58431: 29.0.50; [Eglot] Add "breadcrumb.el" feature based, on imenu.el/project.el services

[Adam Porter <adam@alphapapa.net>]

Daniel Martín <mardani29 <at> yahoo.es> writes:

>> This is similar to which-func.el, which displays the trailing element of
>> the breadcrumb in the headerline.  Perhaps the breadcrumb feature can be
>> thought of as an augmentation of which-func.el's functionality.  I don't
>> have a strong opinion there.
> 
> I see this feature as an augmentation of which-func.el.  The purpose is
> to show what is the current defun, but the how and where (mode line or
> header line) is a configuration option.
> 
> In recent versions of IDEs and text editors another header line UI to
> show the current function is getting popular, something like our old
> Sticky Function mode.  As with this breadcrumb UI, I think its logic
> belongs more to which-func-mode.el and shouldn't be coupled to Semantic.

FWIW, this sounds similar to the topsy.el library I published on MELPA a 
couple of years ago.  It aims to provide similar (or better) 
functionality than semantic-stickyfunc-mode without using Semantic.

https://github.com/alphapapa/topsy.el

If any of its code would be helpful, I'd be glad to "donate" it to 
ELPA/Emacs.