Re: Export of this table fails LuaLaTeX compilation

[gerard.vermeulen@posteo.net]

On 12.10.2022 18:21, Max Nikulin wrote:
[...]
>>> Stewart Thomas. [BUG] Tables with square brackets do not compile in
>>> PDF (latex) export. Wed, 10 Nov 2021 11:16:10 -0500.
>>> https://list.orgmode.org/CAO12V+wB18nAN0FuDPAeN94GHdt_2nbdJtc4u7n4W3HAZbaZsA@mail.gmail.com
>>> 
>>> 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.
>>> 
>>> I just have realized that some users might take advantage of earlier
>>> behavior as a feature:
>>> 
>>> - item \\
>>>   [1cm]
>>> - item
>>> 
>>> I think that [1cm] should be treated as text, however I have no idea
>>> how to allow users to specify amount of vertical space and to not
>>> limit line break to LaTeX only. @@latex:\\[1cm]@@ is not suitable 
>>> when
>>> the same text should be exported to ascii, html, etc.
[...]
> Adding \relax is my fault, I did not expect that it may break \hline.
> Such behavior should be stable over decades. The question is how to
> allow users to have square brackets in the beginning of the line
> following \\ and not break some use case.
> 
>> 2. On my systems ws-butler removes the trailing whitespace.
>> 3. I edited your example with nano to add the trailing space after 
>> \relax, but it still does not compile.
> 
> Sorry, I did not get your point with trailing space. LaTeX ignores
> spaces after commands (e.g. "a\relax b" becomes "ab") and in the
> beginning of the line. What I am afraid of is unintentionally
> introduce white space at the beginning of the line, e.g. if
> | a |
> | b |
> |---|
> is exported as
> {} a \\
> {} b \\
> \hline
> then cell contents will be " a" and " b", not "a" and "b".
> \relax a \\
> \relax b \\
> \hline
> has no such problem.

Sorry, I have misread or misunderstood what \relax does with spaces.
Thank you for your patient explanation -- Gerard