anchor.diff:                          match evalApply [fn; acc; elem] fnOriginOpt world with
                           | (Option (Some value), world) -> (Right (value, value :: accs, world))
                           | (Option None, world) -> Left (List accs, world)
  -                        | _ -> Left (Violation ([!!"InvalidResult"; !!"Container"; !!(String.capitalize fnName)], "Function " + fnName + "'s folder must return an option.", fnOriginOpt), world))
  +                        | _ -> Left (Violation ([!!"InvalidResult"; !!"Container"; !!(String.capitalize fnName)], "Function " + fnName + "'s scanner must return an option.", fnOriginOpt), world))
                           (Right (state, [], world))
                           (Map.toList map)
                   match eir with
  
positive.code:                 | _ -> (Violation ([!!"InvalidArgumentType"; !!"Container"; !!(String.capitalize fnName)], "Incorrect number of arguments for application of '" + fnName + "'; 2 string arguments required where the first is of length 1.", fnOriginOpt), world)
              | [evaledArg; Option opt] ->
                  match opt with
                  | Some _ -> (Violation ([!!"InvalidArgumentType"; !!"Option"; !!(String.capitalize fnName)], "Cannot cons onto a some value.", fnOriginOpt), world)
                  | None -> (Option (Some evaledArg), world)
              | [evaledArg; List list] ->
                  (List (evaledArg :: list), world)
  
negative.code:                         ([], world)
                  if List.forall (function String str when String.length str = 1 -> true | _ -> false) list
                  then (String (list |> List.rev |> List.map (function String str -> str.[0] | _ -> failwithumf ()) |> String.implode), world)
                  else (Violation ([!!"InvalidResult"; !!"Container"; !!(String.capitalize fnName)], "Function " + fnName + " applied to string's mapper must return a string of length 1.", fnOriginOpt), world)
              | [fn; Codata codata] ->
                  let (codata, world) = evalMapCodata evalApply fnOriginOpt fn codata world
                  (Codata codata, world)
  