etags-regen-mode: handling extensionless files

[Sean Whitton <spwhitton@spwhitton.name>]

Hello Dmitry,

I'm working on a Perl project which has .pm files (which should be added
to etags-regen-file-extensions; I've written mail about that) but also
programs intended for execution, which have no file extension:
    <https://salsa.debian.org/dgit-team/dgit>.
E.g. 'dgit' and 'git-debrebase' in the project root.

On the one hand, it makes sense not to index these files because they're
programs not libraries, so their internal definitions won't ever be
referenced elsewhere.

On the other hand, it would be nice just to be able to use a simple
M-. to jump to definition, and not have to think about whether the
function is defined in the program or in a library.

Should we have some etags defcustom that allows specifying extra files
to index?  Or, as another idea, maybe etags could somehow include
looking at what imenu finds?  Might be too clever.

Let me know what you think about this use case.

-- 
Sean Whitton