fun sum [t] (_ : num t) [fs ::: {Unit}] (fl : folder fs) (x : $(mapU t fs)) = @foldUR [t] [fn _ => t] (fn [nm :: Name] [rest :: {Unit}] [[nm] ~ rest] n acc => n + acc) zero fl x fun main () = return {[sum {A = 0, B = 1}]}
{[sum {C = 2.1, D = 3.2, E = 4.3}]}