color in before=

[Hans van der Meer <hansm@science.uva.nl>]

I want to put a color command in a "before" command, that command  
being inserted in a macro.
Something like \setupxyz[before=\color[green]{whatever}]

The problem is that the argument parser gets confused when []- 
expressions are found within the setup.
It is not an option to reprogram everything with {}'s instead of  
[]'s, because then I lose to much of ConTeXt's abilities (apart from  
the nuisance of having to reprogram something that has already been  
done).

I suspect there is no way of sneaking in these []'s inside the  
command? That is the general solution.

My eyes spotted something like \dowithcolor#1#2, but there TeX  
complains about not knowing \od.

Is there a solution to this problem?

yours sincerely,
dr. H. van der Meer