# Badness <img src='https://raw.githubusercontent.com/jolars/badness/main/branding/logo.svg' align="right" width="120" />
[](https://github.com/jolars/badness/actions/workflows/build-and-test.yml)
[](https://github.com/jolars/badness/actions/workflows/lint.yml)
[](https://jolars.github.io/badness/)
[](https://open-vsx.org/extension/jolars/badness)
[](https://marketplace.visualstudio.com/items?itemName=jolars.badness)
[](LICENSE)
**Badness** is a formatter, linter, and language server for LaTeX, built on a
lossless concrete syntax tree.
It parses LaTeX once and serves three tools from that tree:
- **Formatter** (`badness format`): deterministic, rule-based layout.
- **Linter** (`badness lint`): diagnostics with source snippets.
- **Language server** (`badness lsp`): both, live in your editor.
The architecture follows [rust-analyzer](https://rust-analyzer.github.io/): a
generic, error-tolerant, hand-written parser produces a lossless tree, semantics
are layered on top as a separate concern, and recomputation is incremental.
badness never *requires* resolving macros or catcodes to succeed—anything it
cannot statically recognize degrades to generic nodes rather than a crash. Two
properties hold by construction and are enforced as tests: **losslessness** (the
tree reconstructs the input byte-for-byte) and **idempotence** (formatting an
already formatted file changes nothing).
## Installation
Badness is written in Rust. Build from a checkout:
```sh
git clone https://github.com/jolars/badness
cd badness
cargo install --path .
```
### VS Code extension
If you use VS Code or a compatible editor (such as Positron or Cursor), install
the [Badness
extension](https://marketplace.visualstudio.com/items?itemName=jolars.badness)
from the VS Code Marketplace or the [Open VSX
extension](https://open-vsx.org/extension/jolars/badness). It bundles the
`badness` binary and starts the language server automatically when you open a
`.tex` file.
## Usage
```sh
# Format a file in place (or stdin → stdout with no path)
badness format paper.tex
# Verify formatting without writing — exits non-zero if anything would change
badness format --check paper.tex
# Lint, reporting parse diagnostics
badness lint paper.tex
# Run the language server over stdio
badness lsp
```
Formatter style is set through flags: `--line-width` (default `80`),
`--indent-width` (default `2`), and `--wrap` (`reflow` by default; also
`preserve`, with `sentence`/`semantic` planned). See the documentation for the
full reference.
## Documentation
Full documentation lives at **<https://jolars.github.io/badness/>** (built with
mdBook from [`docs/`](docs/)).
## Contributing
Architecture, tenets, and conventions are documented in
[`AGENTS.md`](AGENTS.md), written for both human and AI contributors. In short:
keep the syntactic layer free of semantic knowledge, every parser feature needs
corpus and snapshot tests plus a losslessness assertion, and code stays
`rustfmt`-clean with `clippy` warnings treated as errors.
## License
[MIT](LICENSE)