For a while I have the following question. Is \\{} have the same
effect on tabularray parser as \\\empty?
Throw an error before \hline.
It is possible to use
\begin{tblr}[expand=\empty]{rl}
but I would prefer to reserve such feature for a more nobble purpose.
I've had a
first look at tabularray.sty, but I'm not familiar enough with the new
LaTeX 3 syntax and, frankly, I'm lost...
While it is not easy for me to read code LaTeX2e core and packages, I
should say that I have no guess at all when I am looking at tabularray
sources. It is a completely different language.
I have started a discussion requesting for a \\-like command without
optional arguments. Maybe somebody will suggest a better workaround instead.
https://github.com/lvjr/tabularray/discussions/321
I've tried all the packages involved in tables that I can think of
(longtable, siunitx, tabularx, booktabs, array, and I don't know if I
forgot any) and in all of them the \empty solution works fine. It seems
that tabularray is the black sheep here.
I think tabularray is unique with a regexp-based parser. I had a hope
that new approach does not allow newline between \\ and its arguments,
but unfortunately compatibility with older code is preserved in this aspect.
From LaTeX companion I remember supertabular as an alternative for
longtable, but I am unsure if it is alive yet.
