Badness
Badness is a language server, formatter, and linter for LaTeX.
It parses LaTeX into a lossless concrete syntax tree and builds three tools on top of it:
- a formatter (
badness format) that lays out source deterministically, - a linter (
badness lint) that reports diagnostics, and - a language server (
badness lsp) that brings both to your editor, as well as many other features.
The architecture follows rust-analyzer: a generic, error-tolerant, hand-written parser produces a lossless tree, semantics are layered on top as a separate concern, and recomputation is incremental.
The Architecture
Badness treats input as generic TeX surface syntax. It never requires resolving macros or catcodes to succeed—doing that in full generality is equivalent to running a TeX engine, so anything it cannot statically recognize degrades to generic nodes rather than a crash. Two properties are guaranteed by construction and enforced as test oracles:
- Losslessness: the parsed tree reconstructs the input byte-for-byte.
- Idempotence: formatting an already-formatted file changes nothing.
Where to Go Next
- Installation: get the
badnessbinary. - Getting Started: format and lint your first file.
- Playground: try the formatter in your browser.
- Editor Setup: wire up the language server.
Funding
I am grateful for the financial support offered by the TeX Users Group through the TeX Development Fund.
