Re: Bad interaction between new interpretation of underscore and modules

[Wolfgang Schuster <schuster.wolfgang@googlemail.com>]

Am 13.01.2011 um 17:18 schrieb Mathieu Boespflug:

> Hi all,
> 
> today's beta introduced a really strange problem. Consider two source files:
> 
> definitions.tex:
> \startmodule[definitions]
> \def\lambdax{\lambda_x}
> \stopmodule[definitions]
> 
> main.tex:
> \usemodule[definitions]
> \starttext
> blah $\lambdax$ blah.
> \stoptext
> 
> This results in the following compile error:
> 
> ! Undefined control sequence.
> \lambdax ->\lambda_x
> 
> l.5 blah $\lambdax
>                  $ blah.
> ?
> 
> However, if you change "\usemodule[definitions]" into "\input
> definitions" instead, then there is no compile error! My understanding
> is that the underscore is a valid character for macro names now
> outside of math mode, which is what is causing the problem. But I
> really don't understand what magic is going on in the modules code to
> trigger this.
> 
> I would be very interested in an explanation of what is going on.

You need \normalsubscript in your module. You define a command and
in this case it doesn’t matter that you plan to use it in math mode,
the _ is now a normal letter like “a” and this won’t change when you
call \lambdax in your document.

Write

  \def\lambdax{\lambda\normalsubscript x}

and it will work again.

Wolfgang

___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage  : http://www.pragma-ade.nl / http://tex.aanhet.net
archive  : http://foundry.supelec.fr/projects/contextrev/
wiki     : http://contextgarden.net
___________________________________________________________________________________