Re: which-func, imenu, AUCTeX

[Greg Bognar]

Hi Arash,

Thanks for the (always) helpful explanation and pointers!

So (since I'm not very competent in elisp) are you suggesting that one way to
get what I want would be to write a function (perhaps starting from
`TeX-current-defun-name') that returns only what I want and than set the
`which-func-functions' variable to this function, like below with
`add-log-current-defun-function'?

All the best,
Greg

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On Wed 16 Oct 2024 at 07:31 Arash Esbati wrote:
> 
> Hi Greg,
> 
> Greg Bognar via General discussion about AUCTeX <auctex@gnu.org> writes:
> 
> > I like to display the section (chapter, etc.) name on the modeline by using
> > which-func.  If I understand correctly, which-func uses imenu to get the
> > function (section, etc.) names, and AUCTeX supports imenu by setting
> > `imenu-create-index-function' to `LaTeX-imenu-create-index-function'.
> 
> I only had a brief look, and IIUC, which-func uses the function
> `which-function' to gather the current function name for the modeline:
> 
> ,----[ C-h f which-function RET ]
> | which-function is a interpreted-function in ‘which-func.el’.
> | 
> | (which-function)
> | 
> | Return current function name based on point.
> | Uses ‘which-func-functions’, ‘add-log-current-defun’.
> | or ‘imenu--index-alist’
> | If no function name is found, return nil.
> | 
> `----
> 
> As you see, it uses `add-log-current-defun' before `imenu--index-alist'.
> And latex.el contains:
> 
>   (setq-local add-log-current-defun-function #'TeX-current-defun-name)
> 
> So what happens is that the value of `which-func-functions' is nil, so
> `TeX-current-defun-name' is used for the current function, which indeed
> returns things like "section{My Section}" or "chapter{My Chapter}".
> 
> I think the way to change this is by adding an appropriate function to
> `which-func-functions' which comes first.
> 
> > Is there a way to modify `LaTeX-imenu-create-index-function' (if
> > that's indeed the culprit) so that it only returns the section
> > (chapter, etc.) name without the \-less section (chapter, etc.)
> > command?
> 
> That function works as expected.  Take this example:
> 
> --8<---------------cut here---------------start------------->8---
> \documentclass{article}
> 
> \usepackage{titlesec}
> 
> \titlespacing\section{0pt}{2\bigskipamount}{\parskip}
> 
> \begin{document}
> 
> \section{First section}
> \label{sec:first-section}
> 
> \subsection{This is a subsection}
> \label{sec:this-subsection}
> 
> 
> \section{Second section}
> \label{sec:second-section}
> 
> \end{document}
> --8<---------------cut here---------------end--------------->8---
> 
> and do 'M-x (LaTeX-imenu-create-index-function) RET' which returns:
> 
> --8<---------------cut here---------------start------------->8---
> (("article" . #<marker at 1 in xparse-test.tex>)
>  ("document" . #<marker at 104 in xparse-test.tex>)
>  ("  First section" . #<marker at 122 in xparse-test.tex>)
>  ("    This is a subsection" . #<marker at 173 in xparse-test.tex>)
>  ("  Second section" . #<marker at 237 in xparse-test.tex>)
>  ("document" . #<marker at 290 in xparse-test.tex>))
> --8<---------------cut here---------------end--------------->8---
> 
> > And that it does not pick up things like \titlespacing\section{0pt}?
> 
> See above.
> 
> > (Interestingly, the items that appear in the imenu menu on the menubar are
> > slightly different than the items that are displayed on the modeline.)
> 
> See above.
> 
> FWIW, the builtin latex-mode does exactly the same thing.
> 
> Best, Arash