feat: defines a tree-sitter based Motoko mode for Emacs

[christoph-dfinity]

Motivation

The existing motoko-model.el in this repo is based on swift-mode, which is a bit sad.

With Emacs 29+ we finally got built-in tree-sitter support, so now it's relatively easy to get nice syntax highlighting and auto-indentation behaviour. Most of the actual work was done by this grammar author: https://github.com/polychromatist/tree-sitter-motoko

This is pretty bare-bones, but I intend on adding a few rules here or there as I spot things that don't highlight or indent nicely.

Setup

Add this line to your config:

(load "/path/to/motoko-ts-mode.el")

and run treesit-install-language-grammar, pass motoko as the grammar name and https://github.com/christoph-dfinity/tree-sitter-motoko as the grammar repo. The remaining prompts can stay as defaults.

Afterwards opening .mo files should give you highlighted files with basic indentation support.

[ggreif]

I have GNU Emacs 29.2, very much welcoming this addition!

[ggreif]

Rubber-stamping! I see a surprisingly small amount of code, but I'm happy to test it. (Looks like the grammar repo has the meat.)

[github-actions]

Comparing from b29193b to ebd2652:
The produced WebAssembly code seems to be completely unchanged.

[ggreif]

@Mergifyio refresh

[mergify]

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[crusso]

Good stuff!

[christoph-dfinity]

@Mergifyio refresh

[mergify]

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