Re: etags - Word separators with xref-find-definitions

[Christian Barthel <bch@online.de>]

On Sun, Jul 25 2021, Eli Zaretskii wrote:

>> Is it possible to customize the xref function such that it
>> recognize ‘schema.objectname’?  Are there any variables to
>> control the behavior of M-. ?
>
> You need to customize the etags.el function that is used to guess the
> symbol at point.  The function is this:
>
>   (defun find-tag--default ()
>     (funcall (or find-tag-default-function
> 		 (get major-mode 'find-tag-default-function)
> 		 #'find-tag-default)))
>
> So either customizing find-tag-default-function to point to a function
> of your choice, or making such a function local to the SQL major mode
> by putting the property on the major-mode's symbol, should do the
> job.  You will probably need to write the function itself, though.

OK, thanks so far.  My first draft for this looks something like
this:

--8<---------------cut here---------------start------------->8---
(defun find-sql-identifier ()
  (when (thing-at-point-looking-at
         "\\([.a-zA-Z0-9]*\\)" 50)
    (if (match-beginning 1)
	(buffer-substring (match-beginning 1) (match-end 1))
      "")))
(put major-mode 'find-tag-default-function 'find-sql-identifier)
--8<---------------cut here---------------end--------------->8---

This works for my contrived SQL file as expected, but I guess
that I need some further improvements when using this on a larger
sql code repository .

I think that I will execute the put function (setting
find-tag-default-function) in the sql-mode-hook or is there a
better place to do this?

-- 
Christian Barthel