Rules with advanced constructs

[id: rmketmrrhqurrryu] iSaid(what did you eat today?)
  && input($$x) 
  && fact($$x is a type of food)
  => fact(Today: {You ate $$x})

[id: qwdoknwuxzjjbgwm] iSaid(what did you eat today?)
  && input($$x) 
  && unknownIf($$x is a type of food)
  => o(Is $$x a type of food?)