[tex-k] [NTG-pdftex] Bug#458059:

[Morten Høgholm]

On Sun, 01 Jun 2008 01:55:24 +0200, Karl Berry wrote:

>     The attached file gives an error
>
> Stijn, I'm not sure if you ever found the resolution.
>
[...]
> You can see the loop, \makebm ends up calling itself.
>
> Evidently \makebm cannot be used in \everymath.  Even a complete
> re-archiTeXture will not help :).

The problem is this: When bm encounters a group such as happens in this  
case in the superscript, it will call \bm at mchoice defined thusly:
   \def\bm at mchoice#1#2#3#4#5{%
     \mathchoice{\hbox{#1$\displaystyle\m at th#2$}}%
                {\hbox{#1$\textstyle\m at th#3$}}%
                {\hbox{#1$\scriptstyle\m at th#4$}}%
                {\hbox{#1$\scriptscriptstyle\m at th#5$}}}

Exiting and entering mathmode like this triggers \everymath and so our  
infinite recursion is started. Easiest remedy is to also tell \everymath  
to reset itself.
   \renewcommand*\descriptionlabel[1]{%
     \hspace\labelsep
     {\everymath{\everymath{}\makebm}\normalfont\bfseries #1:}%
   }

-- 
Morten