On 26/08/2011, at 3:04 AM, Ulrike Fischer wrote: > Now I want to define a "mirrored" key > > no-sym > > so that "no-sym = true" sets \l_chessfss_sym_bool to false. > > Is there some easy way? Not directly as far as I know (using .code:n = { \bool_set_false:N \l_chessfss_sym_bool } works of course but it's not the best interface), so I think this would be a good addition. (I seem to remember kvoptions has a similar feature.) Which do you think is best to name it? no-sym .bool_unset:N = \l_chessfss_sym_bool no-sym .bool_set_false:N = \l_chessfss_sym_bool no-sym .bool_set_reverse:N = \l_chessfss_sym_bool Cheers, -- Will