Thanks Heiko!

On 24/04/2009, at 6:51 PM, Heiko Oberdiek wrote:

> %%% begin of fixed definition %%%
> \def\in@#1#2{%
>  \def\in@@##1#1##2\in@@{%
>    \def\in@@{##2}%
>    \ifx\in@@\@empty
>      \in@false
>    \else
>      \in@true
>    \fi
>  }%
>  \in@@#2\@nil#1\in@@
> }
> %%% end of fixed definition %%%

This looks good to me. It seems that the old documentation for the  
command was also written incorrectly:

%    |\@in| is a utility macro with two arguments.  It determines
%    whether its first argument occurs in its second (after expanding
%    it) and sets the switch |\if@in| accordingly.

Unless I'm mistaken, there was no expanding going on in the old  
version; I'm going to change this accordingly.

Any objections to changing the definition to that proposed by Heiko  
above?

Cheers,
Will