[tex4ht] Issues with unpaired brackets

[Michal Hoftich]

Hi all,

incidentally, I found one issue in documents compiled to MathML, from
two independent sources. Meaningless MWE:


    \documentclass{article}
    \begin{document}
    [this is for test $a+b=c]$
    \end{document}

What is important is `]` at the end of inline math. It produces the
following result with `mathml` option:


    <!--l. 3--><p class="noindent" >[this is for test <!--l. 3--><math 
     xmlns="http://www.w3.org/1998/Math/MathML"  
    display="inline" ><mi 
    >a</mi> <mo 
    class="MathClass-bin">+</mo> <mi 
    >b</mi> <mo 
    class="MathClass-rel">=</mo> <mi 
    >c</mi></mrow><mo 
    class="MathClass-close">]</mo></mrow></math>
    </p> 

The issue is that there are two clossing `</mrow>` tags, but none is
opened. I've found that it can be fixed using `mathml-` option:


    <!--l. 3--><p class="noindent" >[this is for test <!--l. 3--><math 
     xmlns="http://www.w3.org/1998/Math/MathML"  
    display="inline" ><mi 
    >a</mi> <mo 
    class="MathClass-bin">+</mo> <mi 
    >b</mi> <mo 
    class="MathClass-rel">=</mo> <mi 
    >c</mi><mo 
    class="MathClass-close">]</mo></math>
    </p> 

It seems that one must use paired brackets (they don't have to be the
same kind $(a+b=c]$ works as well) with default tex4ht configuration.
Every opening bracket add two opening `<mrow>` tags and closing bracket
closes that.

As I am not math expert, my question is: 
Is the original example actually correct? Shouldn't be all brackets
paired, or is the default tex4ht configuration wrong in assuming this? I
know that one must use \left. if there is no opening bracket for
\right). Is there similar mechanism for normal brackets?

Could anybody test if `mathml-` option gives correct results for more
complicated real world examples? 

Best regards,
Michal