[texhax] HTML specials with '_' character

Toby Cubitt tsc25 at cantab.net
Fri Feb 22 17:51:37 CET 2008

Oleg Katsitadze wrote:
> On Sun, Feb 17, 2008 at 08:27:54PM +0100, Michael M. Tung wrote:
> So, why use @ in macro names?  That's the common trick to make
> "hidden" macros, which can't be called by the end user.  For this to
> work, you have to temporarily change catcode of @ to 11 ("letter") so
> that you can use it to define your hidden macros (this is the part
> Reinhard omitted), and when you are done, change the catcode back to
> 12, to prevent users from calling hidden macros.  Something like:
>   \catcode`@=11
>   \def\@mailto#1{...}
>   <other definitions of (or calling the) hidden macros>
>   \catcode`@=12

They probably don't exist in plain TeX, but maybe it's worth adding that 
in LaTeX packages these specific catcode changes should always be 
performed using the \makeatletter and \makeatother macros:

    <other definitions of (or calling the) hidden macros>


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