-> (Out = ['Error', UpdatedValue, 'BadType'])
     ; (nb_setarg(1, State, UpdatedValue), Out = State) ).

% Fetch all values from a state
'get-state'(StateNameOrInstance, Values) :-
    fetch_or_create_state(StateNameOrInstance, State),
    arg(1, State, Values).

'new-state'(Depth,Self,Init,'State'(Init, Type)):- check_type->get_type(Depth,Self,Init,Type);true.

'new-state'(Init,'State'(Init, Type)):- check_type->get_type(10,'&self',Init,Type);true.

fetch_or_create_state(Name):- fetch_or_create_state(Name,_).
% Fetch an existing state or create a new one

fetch_or_create_state(State, State) :- is_valid_nb_state(State),!.
fetch_or_create_state(NameOrInstance, State) :-
    (   atom(NameOrInstance)
    ->  (is_registered_state(NameOrInstance)
        ->  nb_bound(NameOrInstance, State)
        ;   init_state(NameOrInstance),
            nb_bound(NameOrInstance, State))
    ;   is_valid_nb_state(NameOrInstance)
    ->  State = NameOrInstance
    ;   writeln('Error: Invalid input.')
    ),
    is_valid_nb_state(State).

% =================================================================
% =================================================================
% =================================================================
%  GET-TYPE
% =================================================================
% =================================================================
% =================================================================
type_cast(Depth,Self,Val,Into,Casted):-
    get_type(Depth,Self,Val,From),
    (type_accepted_from(Into,From)
     ->Casted=Val
      ;Casted=['Error',Val,'BadType',Into]).

type_accepted_from(Into,From):-Into=From,!.
type_accepted_from(Into,From):-wdmsg(type_accepted_from(Into,From)).


%use default self
eval_20(Eq,RetCasted,Depth,Self,['type-cast',Val,Into,Self],Casted):-current_self(Self),!,
eval_20(Eq,RetCasted,Depth,Self,['type-cast',Val,Into],Casted).

%use other space
eval_20(Eq,RetCasted,Depth,Self,['type-cast',Val,Into,Other],Casted):-!,
    into_space(Depth,Self,Other,Space),
    eval_20(Eq,RetCasted,Depth,Space,['type-cast',Val,Into],Casted).

eval_20(_Eq,_RetCasted,Depth,Self,['type-cast',Val,Into],Casted):-is_list(Val),!,
    catch_metta_return(type_cast(Depth,Self,Val,Into,Casted),CastedM),
    var(CastedM).

eval_20(Eq,RetCasted,Depth,Self,['type-cast',Val,Into],CastedO):-!,
    if_or_else(type_cast(Depth,Self,Val,Into,Casted),Casted=Val),
    %term_singletons(Casted,[]),
    %Casted\==[],Casted\==Val,Into,!,
    do_expander(Eq,RetCasted,Casted,CastedO).


eval_20(_Eq,_RetType,Depth,Self,['get-types',Val],TypeO):- !,
    get_types(Depth,Self,Val,TypeO).

% use default self
eval_20(Eq,RetType,Depth,Self,['get-type',Val,Self],Type):- current_self(Self), !,
    eval_20(Eq,RetType,Depth,Self,['get-type',Val],Type).

% use other space
eval_20(Eq,RetType,Depth,Self,['get-type',Val,Other],Type):- !,
    into_space(Depth,Self,Other,Space),