-type attribute_name() :: required_variable | override_variable.

-type error() :: {error, error_type(), reason()}.

-type error_type() :: atom().

-type maybe_module_attribute() :: module_attribute() | term().

-type maybe_module_config() :: {ok, [module_parameter()]} | error().

-type maybe_update_fun() :: update_fun() | fun((_, _) -> any()).

-type maybe_update_method() :: update_method() | term().

-type maybe_verification_fun() :: verification_fun() | fun((_) -> any()).

-type maybe_verification_method() :: verification_method() | term().

-type mfa(Arity) :: {module(), atom(), Arity}.

-type module_attribute() ::
          #{name := name(),
            description := unicode:chardata(),
            default_value => value(),
            verification => verification_method(),
            update => update_method()}.

-type module_parameter() ::
          #module_parameter{name :: name(),
                            mod :: module(),
                            value :: value(),
                            description :: unicode:chardata(),
                            scope :: scope(),
                            verification_fn :: maybe_verification_fun(),
                            update_fn :: maybe_update_fun() | read_only}.

-type name() :: atom().

-type one_of() :: [value(), ...].

-type reason() :: any().

-type scope() :: local | global.

-type update_fun() :: fun((ParamName :: name(), NewValue :: value()) -> any()).

-type update_method() :: read_only | none | mfa(2) | update_fun().

-type value() :: any().

-type verification_fun() ::
          fun((Value :: value()) -> boolean() | {true, NewValue :: value()} | {false, reason()}).

-type verification_method() :: none | one_of() | mfa(1) | verification_fun().