Trying to get an overview of the LaTeX source code base

[Joseph Wright]

On 06/05/2022 02:13, Aaron Gray wrote:
> Hi,
> 
> I am trying to see how LaTeX fits together, does it sit on TeXLive ?
> 
> Is it still running on the Knuth's old PASCAL2C translated kernel ?
> 
> Are there any good overviews of the code base please ?
> 
> Regards,
> 
> Aaron

I assume you've seen https://tug.org/levels.html or similar.

LaTeX is a macro package, and therefore works with any engine which 
provides the required primitives (built-ins). Today, that set is Knuth's 
TeX + e-TeX + 'pdfTeX extensions'. There are a number of engines that do 
that

- pdfTeX
- XeTeX
- LuaTeX
- e-pTeX
- e-upTeX
- HiTeX/Prote

HiTeX is rather new and experimental, but the others are all widely used.

All except LuaTeX are written in WEB and converted using web2c 
(https://tug.org/texinfohtml/web2c.html) for building binaries. LuaTeX 
is written in C directly.

Whilst TeX Live is a major TeX system, there is also MiKTeX (very 
heavily used on Windows) and KerTeX (restricted to a BSD license and 
therefore suitable in places that GPL code is not acceptable).

Joseph