detex

Port of opendetex to Rust using LLMs.

This Rust port is not 100% compatible with opendetex: the remaining differences are primarily handling of whitespace and line counting.

Building

You can use detex-rs as a library or as a binary with the same interface as C detex.

cargo build -r

This builds a binary called detex. opendetex also has a copy of the binary called delatex which is the same as detex -l, which detex-rs does not implement.

To run the tests, you need the flex library (apt install libfl-dev on Ubuntu) in order to compile opendetex for comparison (the tests will compile it automatically with make -C opendetex-2.8.11).

cargo test

Development

This project was almost entirely written using Claude, but with careful prompting to fix compatibility issues. The main manual work was creating and releasing the crate, and writing this README.

Claude Opus 4.5 did the majority of the work with this prompt, along with detex's detex.l (written in flex, a lexer generator, but largely C code) and detex.h:

Attached is the source code for detex, written in flex and C. Port this to Rust. First make a careful plan to structure the code, then port everything. Try to write idiomatic Rust code.

The initial tests were generated by Claude, then I supplemented with some small test cases extracted from a larger project that demonstrated bugs (discovered by using scripts/compare.sh).

A large bug fix (in handling -s) came from this prompt:

Read detex.l and lexer.rs and make sure they line up exactly. Add comments to lexer.rs along the way citing the correspondence. Change lexer.rs as needed.

Claude wrote the test harness, which compares the Rust and C versions, as well as some initial tests without any detailed instructions.

After that, there were several rounds of adding a new failing test (based on a real writing project, which unfortunately is private because it's a grant proposal) and asking Claude to fix it.