Re: [Emacs-diffs] emacs-25 f8208b6: Document the user-level features of the Xref package

[Dmitry Gutov <dgutov@yandex.ru>]

On 01/20/2016 07:43 AM, Eli Zaretskii wrote:

> "Xref" is the name of the node, not of the section.  And the node's
> name does not mean it describes xref the package; this is user-level
> documentation.  If you have a better suggestion for a short name of a
> node which aims at describing features most of which have "xref-" in
> their names, please tell.

Cross-Referencing? A native speaker might have a better suggestion.

> AFAICT, your additions are not directly related to this section; they
> are not mentioned in it.

Hmm. When I asked what we needed to obsolete tags-loop-continue, you 
only mentioned Dired commands.

http://lists.gnu.org/archive/html/emacs-devel/2016-01/msg00842.html

> No, dired-do-find-regexp cannot replace it, because it looks through
> all the files in the directory, whereas tags-search looks in the files
> recorded in the tags tables.

Ok, dired-do-find-regexp cannot. What about project-or-external-find-regexp?

By default, when the VC project backend is used, and 
project-vc-external-roots-function is at its default value, 
project-or-external-find-regexp will search the current project, as well 
as the directories of the tags tables, if they are outside of it.

Or, in emacs-lisp-mode, it will search the load-path directories.

> We should have an xref-based replacement
> for tags-search and tags-query-replace, which would similarly search
> through the "relevant" files.

tags-query-replace? We have xref-query-replace already, and it's more 
flexible: depending on which results it's called from, it'll perform 
replacements in simple regexp matches, or in "smarter" list of 
references (or other similar kinds of results).

Back to tags-search.

Like described above, we have a command that goes further that it 
already. So what would be the goal of having xref-find-regexp? Just to 
tick off a box and simplify updating the manual?

It will require adding a new method to xref backends, with clear 
semantics and purpose. Backend authors will want to know why they 
implement it, and why a user might want to use xref-find-regexp, instead 
of the aforementioned alternative.

Suppose we're in emacs-lisp-mode. What will xref-find-regexp do? Will it 
search the load-path elements, but skip the current project, however 
it's defined, if it's not in load-path? Will it only search *.el files 
inside load-path directories, and ignore files with all other extensions?

> (Btw, I think replacing tags-search and tags-query-replace with
> commands that start with "project-" is not a good idea, for the same

I definitely never suggested replacing tags-query-replace with project- 
anything. The new "replace" workflow is two-step: two the search (using 
some command that creates an xref buffer), then call xref-query-replace.