[luatex] macro definition inside a callback

[Arno Trautmann]

Khaled Hosny wrote:
> On Fri, Sep 07, 2012 at 08:03:52AM +0200, Arno Trautmann wrote:
>> Hi all,
>>
>> maybe a somewhat strange question again from me: Is it possible to
>> define a macro inside the *_linebreak_filters? I want to use a
>> function in the pre_linebreak_filter, and this function should
>> define a macro. So the macro should be present with a new definition
>> at the beginning of the next paragraph, but only if the previous one
>> has been typeset with that function registered, which removes itself
>> after running.
>
> Why not use some global variable that can be set/checked as appropriate?

Yes, I did it that way now. Still, it would be nice to have the 
possibility. Therefore, I will check Paul's solutions (thanks for that!) 
when I have time to.

Cheers
Arno