Re: [ELPA] New package: mctags

[Eli Zaretskii <eliz@gnu.org>]

> From: chen bin <chenbin.sh@gmail.com>
> Date: Fri, 13 Oct 2017 00:24:17 +1100
> 
> - If there are multiple matches, you can filter the candidates in candidate window.

I think xref-find-definitions, when it uses the etags back-end,
already supports that, doesn't it?

> - the tags file is automatically created in current project.

Yes, but AFAICT, the package uses a somewhat naïve way of generating
TAGS, in effect passing all the non-trivial file names to etags.  Some
projects might use more sophisticated methods, for example see what
src/Makefile does in Emacs to tag both the Lisp and the C names of the
Emacs primitives.

> - if no match found, fallback to `mctags-grep` to grep in current project. So you should always found matched
> string

But the matches found this way are not necessarily definitions, they
can be references.

> - Improvement on performance (for example, ripgrep is automatically used as grep program if installed. GNU
> grep is fallback grep program)

Well, finding a tag via etags.el doesn't require Grep at all.

> - tags file could be automatically updated when user save current file.

Is this really a good idea?  Updating TAGS means you need also revisit
it, which could be a problem in some complex setups, when there's more
than one tag table active at the same time.  OTOH, etags.el is written
in a way that makes frequent updates of TAGS unnecessary.