con meta = fn (db :: Type, widget :: Type) =>
              {Nam : string,
               Show : db -> xbody,
               Widget : nm :: Name -> xml form [] [nm = widget],
               WidgetPopulated : nm :: Name -> db -> xml form [] [nm = widget],
               Parse : widget -> db,
               Inject : sql_injectable db}

fun default [t] (sh : show t) (rd : read t) (inj : sql_injectable t) name : meta (t, string) =
    {Nam = name,
     Show = txt,
     Widget = fn [nm :: Name] => <xml><textbox{nm}/></xml>,
     WidgetPopulated = fn [nm :: Name] n =>
                          <xml><textbox{nm} value={show n}/></xml>,
     Parse = readError,
     Inject = _}

val int = default
val float = default
val string = default
fun bool name = {Nam = name,
                 Show = txt,
                 Widget = fn [nm :: Name] => <xml><checkbox{nm}/></xml>,
                 WidgetPopulated = fn [nm :: Name] b =>
                                      <xml><checkbox{nm} checked={b}/></xml>,
                 Parse = fn x => x,
                 Inject = _}