GNU ELPA - auctex-label-numbers

The package provides a function, auctex-label-numbers-label-to-number, that retrieves label numbers in LaTeX documents. This function is used to implement a global minor mode, auctex-label-numbers-mode, that augments the preview and folding features of AUCTeX:

• Previews of labeled equations are numbered as in the compiled document.
• The macros \ref, \eqref, and \label are folded with the corresponding numbers.
• completion-at-point annotations for the contents of \ref and \eqref include equation numbers.
• Annotations for the command reftex-goto-label.

This package requires AUCTeX, so install that first.

Download this repository, install using M-x package-install-file (or package-vc-install, straight, elpaca, …), and add something like the following to your init file:

(use-package auctex-label-numbers
  :after latex
  :config
  (auctex-label-numbers-mode 1))

With this, the package activates automatically.

You could alternatively use simply (use-package auctex-label-numbers) and activate via M-x auctex-label-numbers-mode or (auctex-label-numbers-mode 1) whenever you'd like (e.g., in the middle of some other customizations of TeX-fold-mode). If you'd like to enable some (but not all) of the provided functionality, then you can extract from the definition of auctex-label-numbers-mode the pieces that you'd like and put those in your config.

The label numbers are retrieved from the aux file of the compiled document. To update them, one should compile the document, regenerate the previews and refresh the folds.

The previews should be numbered automated. To activate the folds, you'll want to make sure TeX-fold-mode is enabled (C-c C-o C-f to toggle) and then fold the buffer (C-c C-o C-b) – see the folding section of AUCTeX's manual for details.

I use the packages tex-continuous.el and preview-auto.el (with the variable preview-auto-refresh-after-compilation is set to its default value, t) to compile the document and regenerate the previews automatically, and refresh the folds as needed using TeX-fold-section (C-c C-o C-s).

By customizing the variable auctex-label-numbers-label-to-number-function, one could specify a different way to retrieve label numbers, e.g., by querying an LSP server.