Tectonic: A modernized, complete, self-contained TeX/LaTeX engine

Co-maintainer here.

Tectonic is a cool project, but hasn't seen any significant changes in a few years---and likely won't anytime soon. It seems we maintainers don't have the time and motivation to put serious work into Tectonic.

I haven't looked at the code in years (and thus may be wrong), but here's a quick overview:

Tectonic's code consists of thin bindings to /harfbuzz/graphite/etc and a vendored XeTeX (in C, with some tweaks to make the build easier), driven by Rust that tries to keep the TeX environment predictable and sane. A few components have been fully ported to Rust (bibtex, spx2html), but the project is very unfinished.

I've looked into the dark corners of TeX when I worked on Tectonic, and it is not pretty. TeX relies on a stack of evil hacks and esoteric behavior that is very hard to replicate, and very difficult to expose in an ergonomic way. This is true of the core system, and of many packages on CTAN.

A quick example: code highlighting does not work in Tectonic. The canonical solution is https://ctan.org/pkg/minted, which spawns a python process to style your code. Reproducibility is one of Tectonic's selling points, so we cannot replicate this behavior.

With https://typst.app/ as good as it is, there's little motivation to modernize TeX---especially considering the effort required. Typst _is_ modern TeX, and I'd rather spend my time there.

I have been using TeX/LaTeX for ages and today same issues hinder the user experience like multiple decades ago - cryptic error messages, complex pipeline, lack of the proper Unicode symbols support out of the box, and so on.

Nowadays, with Typst existing, it's vital for TeX ecosystem to solve these issues, since none of them are present in Typst. Projects like Tectonic would solve this for TeX, but they lack enough hands and (maybe) financial support.

Otherwise, using TeX only makes sense nowadays only if 1) you already have some templates 2) some features are still missing in Typst 3) you are just forced to use TeX/LaTeX for whatever reason.

Background of the project:

Tectonic is forked from the XeTeX TeX engine. However, the build process for XeTeX (and all other mainstream TeX engines) is extremely baroque:

1. The original Knuth sources are written in a language called WEB (which is basically used by nobody else)

2. Those sources are then patched with a series of “change files” due to restrictions on distributing modified sources

3. These patched files are then converted to the Pascal language using some custom processing scripts

4. That Pascal code is then converted to C code using additional custom tools

5. Those C files are then compiled against a set of extension files and libraries written natively in C and C++

One of the big motivators for the launch of the Tectonic project was to break out of this ridiculously unwelcoming development process. Tectonic is based on the C/C++ files that emerge from the XeTeX build process, and is gradually translating that code to modern Rust.

While the core TeX architecture and XeTeX are largely stable, they do, however, evolve with time. This repository recreates the final XeTeX C/C++ files from their source, so that modifications can be ported into the main Tectonic codebase.

https://github.com/tectonic-typesetting/tectonic-staging/blo...

A tool like this is sorely needed for LaTeX, and Tectonic is especially intuitive to embed into other applications, but the divergence of XeTeX from pdflatex makes it incompatible with most Overleaf projects. This is just an unfortunate ecosystem gripe, but for most workflows I end up having to reach for latexmk instead for this reason.