Hi all,

Since Emacs 29 is now released, I’d like to propose adding expreg to ELPA. Expreg can be considered a lite version of expand-region. The notable difference is its use of tree-sitter for language-specific expansions. I also took the liberty to do things differently than expand-region, eg, expreg uses a smaller number of expanders [1]; it is easier to debug when the expansion isn’t what you expected; and it only provides two functions for expansion and contraction, and one variable for adding/removing expanders—no transient maps and other “smart” features, nor different variables to set for each major mode.

The obvious downsides is that, of course, it’s pretty useless on anything other than lisp if you don’t have tree-sitter grammars and major mode installed. You can use it in a non-tree-sitter major mode, as long the tree-sitter grammar exists. You only need to create a parser and expreg will automatically use the parser [2].

I’ve been using it for months and ironed out all sorts of edge-cases, and can recommend it for daily usage.

You can find the repository here: https://github.com/casouri/expreg
And I attached a patch for ELPA. It’s been awhile since I last made a patch for ELPA, I hope I did it right.

[1] Default expanders include: expreg--subword expreg--word expreg--list expreg--string expreg--treesit expreg--comment expreg--paragraph

[2] Something like (add-hook 'xxx-mode-hook (lambda () (treesit-parser-create 'xxx)))

PS. I find it amusing that, among the total 632 LOC, only 17 are responsible for the tree-sitter support, the main purpose of this package; all the rest are code dealing with correctly expanding lists, strings and comments with syntax-ppss.

Thanks,
Yuan