Re: Export of this table fails LuaLaTeX compilation

[Max Nikulin]

On 12/10/2022 14:26, Ihor Radchenko wrote:
> Max Nikulin writes:
> > I can not figure out an easy way to separate \\ from [b] text but to
> > prevent the problem you have discovered. I am unsure if
> >
> >       \\[0pt]
> >
> > has no negative consequences and safe enough. I expect that LaTeX
> > sources are not easy to read when fragile sequences of tokens are involved.
>
> What about adding \relax in front of table rows instead of at the end?
> The hlines are transcoded separately.
>
> All other instances of \\\relax may remain.

If you see a way to implement it, you may try. Do not forget a space 
after it. Spaces at the beginning of line are insignificant, so 
insertion of \relax should not cause more ignored spaces than it was 
before. I would consider skipping "\relax " in the beginning of rows 
where first cell starts from an export snippet.

I am considering \noalign{} instead of \relax. I was never aware of its 
effect, but accordingly to The TeXbook it should keep TeX in vertical 
mode without any action due to empty argument. (Actually I surprised 
that \relax causes any change of internal state besides parser.) 
Unfortunately \noalign{} just as \relax will not allow @@latex:[1cm]@@ 
on the next line, perhaps @@latex:\noalign{\vskip 1cm}@@ is a workaround 
to introduce additional vertical space.

    \\[0pt]

causes insertion of some code for negative vertical skip (of zero height 
this case). It should not be really harmful, but I would avoid this hack.

I never used \\* or \\*[10pt] variants of the command. Current stable 
release should has problems when the line next to \\ starts from * that 
is not bold marker, besides square brackets.