Re: Export of this table fails LuaLaTeX compilation

[Ihor Radchenko <yantar92@gmail.com>]

Max Nikulin <manikulin@gmail.com> writes:

> 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.) 

If \noalign has less side effects compared to \relax, I'd prefer
\noalign. Can you confirm this?

I was also surprised that \relax does anything except escaping.

> 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]

What you are talking about appears to be abusing our exporter. We give
no guarantees about how \\ is going to be exported internally into
LaTeX. We should have no obligation to keep use-cases like this.

> 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.

I feel like I am missing what you are talking about here.

-- 
Ihor Radchenko // yantar92,
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