[NTG-context] conditionals for font features

Dear list, I wonder whether there is a conditional for font features similar to \doifelseitalic. \doifelsecurrentfonthasfeature checks whether the font supports an OpenType feature. \doifunknownfontfeature checks whether the font feature has been defined. It seems that \doifelsefontfeature checks whether the font feature has been defined or not. Could anyone explain me how to check whether c2sc is being used or not in the following sample? \definefontfeature[asc][c2sc=yes, smcp=yes] \setupbodyfont[palatino] \starttext \feature[+][asc] abc\\ \feature[-][asc] abc \stoptext Many thanks for your help, Pablo