[NTG-context] Numbers obtained by commands <\datasetvariable> cannot be copied to counters

I'm defining a command to generate options for multiple choice questions, but at the moment I'm stuck at this step. I want to get a number and assign a value to the counter, but why can't I get it? %%%% \starttext \definedataset [myset] \setdataset [myset] [foo=1,boo=4] \newcount\tempa \datasetvariable{myset}{1}{boo} % definitely get 4 %\tempa=\datasetvariable{myset}{1}{boo} % why i cannt pass 4 to tempa? %\number\tempa \stoptext %%%%% If anyone can fix it, thanka very much Muyik