tex-parens.el: like lisp.el but for tex

Overview

Emacs comes with the following useful commands for working with lists, sexps and defuns (see the info nodes Expressions and Defuns):

bind	command	docstring
C-M-@	mark-sexp	Set mark ARG sexps from point or move mark one sexp.
C-M-a	beginning-of-defun	Move backward to the beginning of a defun.
C-M-b	backward-sexp	Move backward across one balanced expression (sexp).
C-M-d	down-list	Move forward down one level of parentheses.
C-M-e	end-of-defun	Move forward to next end of defun.
C-M-f	forward-sexp	Move forward across one balanced expression (sexp).
C-M-h	mark-defun	Put mark at end of this defun, point at beginning.
C-M-k	kill-sexp	Kill the sexp (balanced expression) following point.
C-M-n	forward-list	Move forward across one balanced group of parentheses.
C-M-p	backward-list	Move backward across one balanced group of parentheses.
C-M-t	transpose-sexps	Like C-t (‘transpose-chars’), but applies to sexps.
C-M-u	backward-up-list	Move backward out of one level of parentheses.
C-M-<backspace>	backward-kill-sexp	Kill the sexp (balanced expression) preceding point.
-	up-list	Move forward out of one level of parentheses.
-	delete-pair	Delete a pair of characters enclosing ARG sexps that follow point.
-	raise-sexp	Raise N sexps one level higher up the tree.

This package provides analogous commands adapted for tex buffers, with the class of parenthesis-like delimiters (namely, parentheses (), brackets [] and braces {}) expanded to include the following:

• \begin{...} - \end{...} pairs
• math environment delimiters $...$, \(...\), \[...\], $$...$$
• mathematical delimiters: parentheses, brackets, braces, \langle - \rangle, \lvert - \rvert, etc., and compositions of these with modifiers such as \left - \right, \Bigg, etc. See M-x customize-group tex-parens for details.

There is some support in this direction in the built-in tex-mode, in AUCTeX and in latex-extra. There are many packages, such as paredit and lispy, that add further useful commands and bindings to lisp modes, and many other packages, such as smartparens, puni and paredit-everywhere, that aim to give consistent parenthesis-based commands across all modes. There’s also the evil-tex package for those that prefer a modal setup. I was unable to get these packages to behave in the desired manner. Smartparens comes close, but doesn’t seem to support arbitrary begin/end pairs, and has some issues when one delimiter is a prefix of another (Fuco1/smartparens#1193). This package should work out-of-the-box and behave in tex buffers just like stock Emacs does in lisp buffers.

Configuration

This package is available via GNU ELPA, so you can install it using package-install or list-packages. You can activate it via M-x tex-parens-mode, which remaps binds for the commands listed above to their tex-parens-* counterparts.

To activate automatically, add the following lines to your config (the first hook applies if use the built-in tex-mode, the second if you use AUCTeX):

(use-package tex-parens
  :hook
  (tex-mode . tex-parens-mode)
  (TeX-mode . tex-parens-mode))

For finer control over how keys are bound, you can avoid tex-parens-mode and instead use something like the following:

(use-package tex-parens
  :bind
  (:map LaTeX-mode-map
        ("C-M-f" . tex-parens-forward-sexp)
        ("C-M-b" . tex-parens-backward-sexp)
        ("C-M-n" . tex-parens-forward-list)
        ("C-M-p" . tex-parens-backward-list)
        ("C-M-u" . tex-parens-backward-up-list)
        ("M-u" . tex-parens-up-list)
        ("C-M-g" . tex-parens-down-list)
        ("M-_" . tex-parens-delete-pair)
        ("C-M-SPC" . tex-parens-mark-sexp)
        ("C-M-k" . tex-parens-kill-sexp)
        ("C-M-t" . tex-parens-transpose-sexps)
        ("C-M-<backspace>" . tex-parens-backward-kill-sexp)
        ("M-+" . tex-parens-raise-sexp))
  :hook
  (tex-mode . tex-parens-setup)
  (TeX-mode . tex-parens-setup))

The precise use-package declaration that I use may be found in the LaTeX part of my config (elpaca branch).

Use M-x customize-group tex-parens to configure further. If you tweak the customization variables concerning delimiters and modifiers, then you’ll need to reload your tex file, reset the minor mode, or do M-: (tex-parens-setup) for the changes to take effect.

Variants

This package contains the additional functions tex-parens-burp-left, tex-parens-burp-right, tex-parens-mark-inner, tex-parens-beginning-of-list and tex-parens-end-of-list, which are defined in terms of the sexp/list primitives; see the C-h f documentation for details.