[NTG-context] run a ruby script and use the standard output ???

Hi all, Is it possible to run a ruby script from a context document during its processing (I already know how to do that using \write18 but there is maybe a better way...) then get the output of the script to display or use it into the document. It's a little bit hard to describe so I have a simple example: \starttext \def\vartest{3.124325234543523452435} \write18{ruby ./myscript.rb \vartest XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX} \stoptext with myscript.rb: temp = ARGV[0] puts "\nXXXXXXXXXXXXX " + (Math::sqrt(temp.to_f)).to_s + " XXXXXXXXXXXXX\n" I would store the result of puts into a variable usable within ConTeXt... Renaud