Hi Thierry, On Mon, Oct 18, 2021 at 5:23 AM LARONDE Thierry <[log in to unmask]> wrote: > > ---8<--- > LaTeX2e <2021-06-01> patch level 1 > inputing expl3.ltx (l3kernel/expl3.ltx (l3kernel/expl3-code.tex > ! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! ! > Argh, internal LaTeX3 error! > > Module kernel, message name "command-already-defined": > Arguments '\@@_use_none_delimit_by_q_recursion_stop:w' and '\long > macro:#1\q_@@ > _recursion_stop ->' > > This is one for The LaTeX3 Project: bailing out. > \msg_error:nnxx ...he LaTeX3 Project: bailing out} > \tex_end:D > l.2946 ...@_use_none_delimit_by_q_recursion_stop:w > --->8--- That is odd. It seems that expl3-code.tex is not properly docstripped from the sources, because control sequences |\@@_...| should not exist in executable code (like expl3-code.tex), only in the sources. Some control sequences across expl3 modules have the same name, except for the module name, denoted by the |@@| prefix, which is replaced by the actual module name by (l3)docstrip. Without the replacement you end up with multiple control sequences with the same name, and you get the error you are seeing. Some time ago the |@@| replacement from l3docstrip was merged into the main docstrip code, so make sure you are using the right version. > So is there anywhere (and please: not the >1500 pages "manual"!) short > explanations about how to add a new engine? What has to be set and > where? No. New engines aren't created every day, so little effort was put into that (zero, in terms of documentation). But from what I've read about Prote, it should take more or less the same code paths as XeTeX, except where the engine is specifically tested for (in which case, what you showed should suffice for the most part of it). Hope it helps. Best, Phelype