Basic formatter for the Typst language with a future!

• Goals
• Features
• State
• Installing
  • Setting up a pre-commit hook
• Contributing
• Architecture
  • Main logic
  • Roadmap
• Testing and visualizing
  • Installing Insta
  • Using insta here
    • Can I see it in action?
    • Is that all I have to help me test?
      • Tracing
      • Fmttest (TO BE IMPLEMENTED)
• Thanks (chronological)

Goals

• Decent output under any circumstances, anything not decent should be reported as a bug!
• Fast, Small, configurable and embeddable library and binary!
• Good default (see roadmap)

Features

• Good defaults.

• Config file: run typstfmt --make-default-config to create a typstfmt.toml file that you can customize!

  The following lines show the contents of a simple typstfmt.toml file:

  indent_space = 2
  max_line_length = 80
  experimental_args_breaking_consecutive = false
  line_wrap = true

• Disable the formatting by surrounding code with // typstfmt::off and // typstfmt::on. (Experimental and broken)

State

It's not always pretty, it sometimes break the code in math mode, but it should be safe for code and markup.

Installing

cargo install --git https://github.com/astrale-sharp/typstfmt.git

Setting up a pre-commit hook

Optionally, you can setup a git hook to format your files at each commit:

echo "set -e

for f in \$(git ls-files --full-name -- '*.typ') ; do
    typstfmt --check \$f --verbose
done" > .git/hooks/pre-commit

chmod +x .git/hooks/pre-commit

Now if you try to commit unformatted files, they will be caught and the commit will fail, telling you which file should be fixed.

Notes:

• You should probably avoid doing this at the moment, as typstfmt is not quite stable yet
• Be careful if you have another commit hook setup, as the command above will replace it entirely!

Contributing

• feel free to open issue or discuss! I don't have github notifications so also feel free to go ping me on the typst discord server (@Astrale).
• once discussed, you may open a PR, not before cause I'm a bit chaotic and this is wip so things change fast and I would hate it if you lost your time.

Architecture

Main logic

Since we're visiting a AST (which is a tree) we have a recursive function visit(node: &LinkedNode, ctx: &mut Ctx) that meets all the nodes in the tree.

It formats the children first (bottom up), then the parent decide what to do with their children.

Children have access to arbitrary context (they can know the kind of their parents, who are their siblings etc).

Roadmap

Once the test suite is large enough and the formatting is satisfying, create an abstraction to make the codebase easier to work with.

One person cannot come up with good formatting default. This will first be configurable and then with experience and opinions from the community, default will be tuned.

Testing and visualizing

Installing Insta

We use insta! If you don't have it installed take a look here (hint: use cargo binstall)

Using insta here

Can I see it in action?

To see how it currently formats all the snippets:

• run cargo test, a failing test indicates one of the snippets displayed in the next step is not formatted like this anymore.
• run show_all.sh

Is that all I have to help me test?

Tracing

Of course not! We have tracing enabled during tests!

If you're contributing tests you should add a test case under src/tests for instance: make_test!(call_func_empty, "#f()");

then running your tests: cargo test && cargo insta review

If the info log isn't enough, run DEBUG=true cargo test. If you wish to pipe to a file run NO_COLOR=true cargo test you may also set the NOLOG env variable if you wish to disable logging entirely.

Fmttest (TO BE IMPLEMENTED)

On the fmttest branch, you can see the skeleton of a program that will automate finding which range, when formatted, was not valid anymore (broke the semantic of the code).

Thanks (chronological)

• @arnaudgolfouse, for the discussion, designs and the precious friendship.
• @laurmaedje, @reknih and the typst community for the good vibes, the interesting talks, the support and ofc, Typst.
• @jeffa5 for contributing ideas on the initial design
• @Andrew15-5, for the many suggestions, issues and feedback.
• @aghriss for a bug fix
• @taooceros for the alignment of math block