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 my config.

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 following additional functions defined in terms of the sexp/list primitives:

• tex-parens-burp-left, tex-parens-burp-right: Slurp or barf sexps in and out of the current list.
• tex-parens-mark-inner: Mark the innermost balanced group around point.
• tex-parens-beginning-of-list, tex-parens-end-of-list: Move to the beginning or end of the current balanced group.
• tex-parens-kill-to-end-of-list, tex-parens-kill-to-beginning-of-list: Kill text between point and the end or beginning of the current list.

See the C-h f documentation for each function for more details. They may be bound in the same manner as described above.

Avy Integration

There are additional commands that use Avy to jump to and copy math expressions:

• tex-parens-avy-jump-to-math: Jump to and enter a math expression using Avy.
• tex-parens-avy-copy-math: Copy a math expression selected using Avy.

To use these commands, make sure you have Avy installed and loaded, then bind them in your config as described above.