work

src/dabmodel/LAMFields/FrozenLAMField.py

@@ -1,41 +0,0 @@
-from typing import Generic, TypeVar, Any
-
-from .LAMField import LAMField
-from .Constraint import BaseConstraint
-from ..tools import LAMdeepfreeze
-
-T_Field = TypeVar("T_Field")
-
-
-class FrozenLAMField(Generic[T_Field]):
-    """FrozenLAMField class
-    a read-only proxy of a Field
-    """
-
-    def __init__(self, inner_field: LAMField):
-        self._inner_field = inner_field
-
-    @property
-    def doc(self) -> str:
-        """Returns Field's documentation (frozen)"""
-        return LAMdeepfreeze(self._inner_field.doc)
-
-    @property
-    def constraints(self) -> tuple[BaseConstraint]:
-        """Returns Field's constraint (frozen)"""
-        return LAMdeepfreeze(self._inner_field.constraints)
-
-    @property
-    def default_value(self) -> Any:
-        """Returns Field's default value (frozen)"""
-        return self._inner_field.default_value
-
-    @property
-    def value(self) -> Any:
-        """Returns Field's value (frosen)"""
-        return self._inner_field.value
-
-    @property
-    def annotations(self) -> Any:
-        """Returns Field's annotation (frozen)"""
-        return LAMdeepfreeze(self._inner_field.annotations)

src/dabmodel/LAMFields/LAMField.py

@@ -1,62 +0,0 @@
-from typing import Generic, TypeVar, Optional, Any
-
-from .LAMFieldInfo import LAMFieldInfo
-from .Constraint import BaseConstraint
-from ..tools import LAMdeepfreeze
-
-T_Field = TypeVar("T_Field")
-
-
-class LAMField(Generic[T_Field]):
-    """This class describe a Field in Schema"""
-
-    def __init__(self, name: str, v: Optional[T_Field], a: Any, i: LAMFieldInfo):
-        self._name: str = name
-        self._source: Optional[type] = None
-        self._default_value: Optional[T_Field] = v
-        self._value: Optional[T_Field] = v
-        self._annotations: Any = a
-        self._info: LAMFieldInfo = i
-        self._constraints: list[BaseConstraint[Any]] = i.constraints
-
-    def add_source(self, s: type) -> None:
-        """Adds source Appliance to the Field"""
-        self._source = s
-
-    @property
-    def doc(self) -> str:
-        """Returns Field's documentation"""
-        return self._info.doc
-
-    def add_constraint(self, c: BaseConstraint) -> None:
-        """Adds constraint to the Field"""
-        self._constraints.append(c)
-
-    @property
-    def constraints(self) -> list[BaseConstraint]:
-        """Returns Field's constraint"""
-        return self._info.constraints
-
-    @property
-    def default_value(self) -> Any:
-        """Returns Field's default value (frozen)"""
-        return LAMdeepfreeze(self._default_value)
-
-    def update_value(self, v: Optional[T_Field] = None) -> None:
-        """Updates Field's value"""
-        self._value = v
-
-    @property
-    def value(self) -> Any:
-        """Returns Field's value (frozen)"""
-        return LAMdeepfreeze(self._value)
-
-    @property
-    def raw_value(self) -> Optional[T_Field]:
-        """Returns Field's value"""
-        return self._value
-
-    @property
-    def annotations(self) -> Any:
-        """Returns Field's annotation"""
-        return self._annotations

src/dabmodel/LAMFields/LAMFieldInfo.py

@@ -1,26 +0,0 @@
-from typing import Optional, Any
-from .Constraint import BaseConstraint
-
-
-class LAMFieldInfo:
-    """This Class allows to describe a Field in Appliance class"""
-
-    def __init__(
-        self, *, doc: str = "", constraints: Optional[list[BaseConstraint]] = None
-    ):
-        self._doc: str = doc
-        self._constraints: list[BaseConstraint]
-        if constraints is None:
-            self._constraints = []
-        else:
-            self._constraints = constraints
-
-    @property
-    def doc(self) -> str:
-        """Returns Field's documentation"""
-        return self._doc
-
-    @property
-    def constraints(self) -> list[BaseConstraint[Any]]:
-        """Returns Field's constraints"""
-        return self._constraints

src/dabmodel/__init__.py

@@ -13,9 +13,12 @@ Main module __init__ file.
 from .__metadata__ import __version__, __Summuary__, __Name__
 
 
-from .LAMFields.LAMField import LAMField
-from .LAMFields.LAMFieldInfo import LAMFieldInfo
-from .LAMFields.FrozenLAMField import FrozenLAMField
+from .meta.element import ClassMutable, ObjectMutable
+from .element import Element
+from .lam_field.lam_field import LAMField
+from .lam_field.lam_field_info import LAMFieldInfo
+
+# from .LAMFields.FrozenLAMField import FrozenLAMField
 from .appliance import Appliance
 from .feature import Feature
 
@@ -25,7 +28,6 @@ from .exception import (
     MultipleInheritanceForbidden,
     BrokenInheritance,
     ReadOnlyField,
-    NewFieldForbidden,
     NotAnnotatedField,
     ReadOnlyFieldAnnotation,
     InvalidFieldValue,
@@ -35,4 +37,9 @@ from .exception import (
     FunctionForbidden,
     InvalidFeatureInheritance,
     FeatureNotBound,
+    UnsupportedFieldType,
+    NonExistingField,
+    InvalidFieldName,
 )
+
+__all__ = [name for name in globals() if not name.startswith("_")]

src/dabmodel/appliance.py

@@ -1,9 +1,71 @@
-from .element import Element
+from .meta.element import IAppliance
 from .meta.appliance import _MetaAppliance
+from .feature import Feature
 
 
-class Appliance(Element, metaclass=_MetaAppliance):
+class Appliance(IAppliance, metaclass=_MetaAppliance):
     """BaseFeature class
     Base class for Appliance.
     An appliance is a server configuration / image that is built using appliance's code and Fields.
     """
+
+    def validate_schema(self):
+        super().validate_schema()
+        for k in self.__lam_schema__["features"]:
+            self.__dict__[k].validate_schema()
+
+    @classmethod
+    def validate_schema_class(cls):
+        super().validate_schema_class()
+        print(cls.__lam_schema__["features"])
+        for v in cls.__lam_schema__["features"].values():
+            v.validate_schema_class()
+
+    def _validate_schema_unknown_attr(self, name: str):
+        if isinstance(self.__dict__[name], Feature):
+            return
+        super()._validate_schema_unknown_attr(name)
+
+    def _validate_schema_missing_attr(self, name: str):
+        if name == "features":
+            return
+        super()._validate_schema_missing_attr(name)
+
+    @classmethod
+    def _validate_unknown_field_schema(cls, name: str):
+        if name == "features":
+            return
+        super()._validate_unknown_field_schema(name)
+
+    def _freeze_unknown_attr(self, name: str, force: bool = False):
+        if isinstance(self.__dict__[name], Feature):
+            self.__dict__[name].freeze(force)
+            return
+        super()._freeze_unknown_attr(name, force)
+
+    def _freeze_missing_attr(self, name: str, force: bool = False):
+        if name == "features":
+            for k, v in self.__lam_schema__["features"].items():
+                v.freeze_class(force)
+            return
+        super()._freeze_missing_attr(name, force)
+
+    @classmethod
+    def _freeze_unknown_field_schema(cls, name: str, force: bool = False):
+        if name == "features":
+            for v in cls.__lam_schema__["features"].values():
+                v.freeze_class(force)
+            return
+        super()._freeze_unknown_field_schema(name, force)
+
+    @classmethod
+    def _validate_unknown_attr_class(cls, name: str) -> None:
+        if issubclass(cls.__dict__[name], Feature):
+            return
+        super()._validate_unknown_attr_class(name)
+
+    @classmethod
+    def _freeze_unknown_attr_class(cls, name: str, force: bool = False) -> None:
+        if issubclass(cls.__dict__[name], Feature):
+            return
+        super()._freeze_unknown_attr_class(name, force)

src/dabmodel/base_element.py

@@ -0,0 +1,253 @@
+from typing import Any, Self, Dict, Optional
+
+from typeguard import check_type, CollectionCheckStrategy, TypeCheckError
+from copy import deepcopy
+
+from .lam_field.lam_field import LAMField, LAMField_Element
+from .exception import ReadOnlyField, SchemaViolation, NonExistingField, InvalidFieldValue
+from .tools import LAMdeepfreeze, is_data_attribute
+
+'''
+class ElementView:
+    __slots__ = ("_vals", "_types", "_touched")
+
+    def __init__(
+        self,
+        values: dict[str, Any],
+        types_map: dict[str, type],
+    ):
+        self._vals: dict[str, Any]
+        self._types: dict[str, type]
+        self._touched: set
+        object.__setattr__(self, "_vals", dict(values))
+        object.__setattr__(self, "_types", types_map)
+
+    def __getattr__(self, name: str) -> Any:
+        """internal proxy getattr"""
+        if name not in self._types:
+            raise NonExistingField(f"Unknown field {name}")
+        return self._vals[name]
+
+    def __setattr__(self, name: str, value: Any):
+        """internal proxy setattr"""
+        if name not in self._types:
+            raise NonExistingField(f"Cannot set unknown field {name}")
+        T = self._types[name]
+
+        try:
+            check_type(
+                value,
+                T,
+                collection_check_strategy=CollectionCheckStrategy.ALL_ITEMS,
+            )
+        except TypeCheckError as exp:
+            raise InvalidFieldValue(f"Field <{name}> value is not of expected type {T}.") from exp
+
+        self._vals[name] = value
+
+    def export(self) -> dict:
+        """exports all proxified values"""
+        return dict(self._vals)
+
+
+class ElementViewCls:
+    __slots__ = ("_vals", "_types", "_touched", "_name", "_module")
+
+    def __init__(
+        self,
+        values: dict[str, Any],
+        types_map: dict[str, type],
+        name: Optional[str] = None,
+        module: Optional[str] = None,
+    ):
+        super().__init__(values, types_map)
+        self._name: str
+        self._module: str
+
+        if name is not None:
+            object.__setattr__(self, "_name", name)
+        if module is not None:
+            object.__setattr__(self, "_module", module)
+
+    @property
+    def __name__(self) -> str:
+        """returns proxified class' name"""
+        return self._name
+
+    @property
+    def __module__(self) -> str:
+        """returns proxified module's name"""
+        return self._module
+
+    @__module__.setter
+    def __module__(self, value: str):
+        pass
+'''
+
+
+class BaseElement:
+    __lam_schema__ = {}
+    __lam_initialized__ = False
+    __lam_class_mutable__ = False
+    __lam_object_mutable__ = False
+    __lam_options__ = {}
+    """
+    def get_model_spec(self, name: str, module: str, memo: dict[str, Any]) -> ElementView:
+        # memo[self.__name__] = {}
+        init_fieldvalues = {}
+        init_fieldtypes = {}
+        for k, v in self.__lam_schema__.items():
+            if isinstance(v, LAMField_Element):
+                memo[k] = {}
+                init_fieldvalues[k] = v.value.get_model_spec(memo[k])
+                # clone = v.clone_unfrozen().value
+            elif isinstance(v, LAMField):
+                clone = deepcopy(v.value)
+                init_fieldvalues[k] = clone
+            else:
+                pass
+            init_fieldtypes[k] = v.annotations
+        return ElementView(init_fieldvalues, init_fieldtypes)
+
+    @classmethod
+    def get_model_spec_cls(cls, memo: dict[str, Any]) -> ElementView:
+        # memo[self.__name__] = {}
+        init_fieldvalues = {}
+        init_fieldtypes = {}
+        for k, v in cls.__lam_schema__.items():
+            if isinstance(v, LAMField_Element):
+                memo[k] = {}
+                init_fieldvalues[k] = v.value.get_model_spec(k, memo[k])
+                # clone = v.clone_unfrozen().value
+            elif isinstance(v, LAMField):
+                clone = deepcopy(v.value)
+                init_fieldvalues[k] = clone
+            else:
+                pass
+            init_fieldtypes[k] = v.annotations
+        return ElementViewCls(init_fieldvalues, init_fieldtypes, cls.__name__, cls.__modules__)
+    """
+
+    def clone_as_mutable_variant(self, *, deep: bool = True, _memo: Dict[int, Self] | None = None) -> Self:
+        raise NotImplemented()
+
+    @classmethod
+    @property
+    def frozen_cls(cls) -> bool:
+        return not cls.__lam_class_mutable__
+
+    @classmethod
+    @property
+    def mutable_obj(cls) -> bool:
+        return cls.__lam_object_mutable__
+
+    @property
+    def frozen(self) -> bool:
+        return not self.__lam_object_mutable__
+
+    def __setattr__(self, key: str, value: Any) -> None:
+        if key.startswith("_"):
+            return super().__setattr__(key, value)
+
+        if key not in self.__lam_schema__:
+            raise NonExistingField(f"Can't create new object attributes: {key}")
+
+        if not self.__lam_object_mutable__:
+            raise ReadOnlyField(f"{key} is read-only")
+
+        self.__lam_schema__[key].validate(value)
+
+        return super().__setattr__(key, value)
+
+    def freeze(self, force: bool = False) -> None:
+        if self.__lam_object_mutable__ or force:
+            if self.__lam_object_mutable__:
+                self.validate_schema()
+
+            setSchemaKeys = set(self.__lam_schema__)
+            setInstanceKeys = {_[0] for _ in self.__dict__.items() if is_data_attribute(_[0], _[1])}
+
+            for k_unknown in setInstanceKeys - setSchemaKeys:
+                self._freeze_unknown_attr(k_unknown, force)
+
+            for k_missing in setSchemaKeys - setInstanceKeys:
+                self._freeze_missing_attr(k_missing, force)
+
+            for k in list(setSchemaKeys & setInstanceKeys):
+                self.__lam_schema__[k].freeze()
+                if isinstance(self.__dict__[k], BaseElement):
+                    self.__dict__[k].freeze(force)
+                else:
+                    self.__dict__[k] = LAMdeepfreeze(self.__dict__[k])
+
+            self.__lam_object_mutable__ = False
+
+    def _freeze_unknown_attr(self, name: str, force: bool = False) -> None:
+        raise SchemaViolation(f"Attribute <{name}> is not in the schema")
+
+    def _freeze_missing_attr(self, name: str, force: bool = False) -> None:
+        raise SchemaViolation(f"Attribute <{name}> is missing from instance")
+
+    def validate_schema(self) -> None:
+        setSchemaKeys = set(self.__lam_schema__)
+        setInstanceKeys = {_[0] for _ in self.__dict__.items() if is_data_attribute(_[0], _[1])}
+
+        for k_unknown in setInstanceKeys - setSchemaKeys:
+            self._validate_schema_unknown_attr(k_unknown)
+
+        for k_missing in setSchemaKeys - setInstanceKeys:
+            self._validate_schema_missing_attr(k_missing)
+
+        for k in list(setSchemaKeys & setInstanceKeys):
+            self.__lam_schema__[k].validate_self()
+
+    def _validate_schema_unknown_attr(self, name: str) -> None:
+        raise SchemaViolation(f"Attribute <{name}> is not in the schema")
+
+    def _validate_schema_missing_attr(self, name: str) -> None:
+        raise SchemaViolation(f"Attribute <{name}> is missing from instance")
+
+    @classmethod
+    def freeze_class(cls, force: bool = False) -> None:
+        if cls.__lam_class_mutable__ or force:
+            cls.validate_schema_class()
+
+            # class should not have any elements so they are all unknown
+            for k_unknown in {_[0] for _ in cls.__dict__.items() if is_data_attribute(_[0], _[1])}:
+                cls._freeze_unknown_attr_class(k_unknown, force)
+
+            for k, v in cls.__lam_schema__.items():
+                if isinstance(v, LAMField):
+                    cls.__lam_schema__[k].freeze()
+                else:
+                    cls._freeze_unknown_field_schema(k, force)
+
+                cls.__lam_class_mutable__ = False
+
+    @classmethod
+    def _freeze_unknown_attr_class(cls, name: str, force: bool = False) -> None:
+        raise SchemaViolation(f"Class attribute <{name}> is not in the schema")
+
+    @classmethod
+    def _freeze_unknown_field_schema(cls, name: str, force: bool = False) -> None:
+        raise SchemaViolation(f"Unknown field <{name} in the schema> ")
+
+    @classmethod
+    def validate_schema_class(cls) -> None:
+        # class should not have any elements so they are all unknown
+        for k_unknown in {_[0] for _ in cls.__dict__.items() if is_data_attribute(_[0], _[1])}:
+            cls._validate_unknown_attr_class(k_unknown)
+
+        for k, v in cls.__lam_schema__.items():
+            if isinstance(v, LAMField):
+                v.validate_self()
+            else:
+                cls._validate_unknown_field_schema(k)
+
+    @classmethod
+    def _validate_unknown_attr_class(cls, name: str) -> None:
+        raise SchemaViolation(f"Class attribute <{name}> is not in the schema")
+
+    @classmethod
+    def _validate_unknown_field_schema(cls, name: str) -> None:
+        raise SchemaViolation(f"Unknown field <{name} in the schema> ")

src/dabmodel/defines.py

@@ -0,0 +1,87 @@
+from typing import Any, Union, Optional, List, Dict, Tuple, Set, FrozenSet, Annotated
+from types import SimpleNamespace
+import math
+
+ALLOWED_MODEL_FIELDS_TYPES: set[type[Any], ...] = {
+    str,
+    int,
+    float,
+    complex,
+    bool,
+    bytes,
+}
+
+ALLOWED_ANNOTATIONS: dict[str, Any] = {
+    "Union": Union,
+    "Optional": Optional,
+    "List": List,
+    "Dict": Dict,
+    "Tuple": Tuple,
+    "Set": Set,
+    "FrozenSet": FrozenSet,
+    "Annotated": Annotated,
+    # builtins:
+    "int": int,
+    "str": str,
+    "float": float,
+    "bool": bool,
+    "complex": complex,
+    "bytes": bytes,
+    "None": type(None),
+    "list": list,
+    "dict": dict,
+    "set": set,
+    "frozenset": frozenset,
+    "tuple": tuple,
+}
+
+
+ALLOWED_HELPERS_MATH = SimpleNamespace(
+    sqrt=math.sqrt,
+    floor=math.floor,
+    ceil=math.ceil,
+    trunc=math.trunc,
+    fabs=math.fabs,
+    copysign=math.copysign,
+    hypot=math.hypot,
+    exp=math.exp,
+    log=math.log,
+    log10=math.log10,
+    sin=math.sin,
+    cos=math.cos,
+    tan=math.tan,
+    atan2=math.atan2,
+    radians=math.radians,
+    degrees=math.degrees,
+)
+
+ALLOWED_HELPERS_DEFAULT: dict[str, object] = {
+    "math": ALLOWED_HELPERS_MATH,
+    "print": print,
+    # Numbers & reducers (pure, deterministic)
+    "abs": abs,
+    "round": round,
+    "min": min,
+    "max": max,
+    "sum": sum,
+    # Introspection-free basics
+    "len": len,
+    "sorted": sorted,
+    # Basic constructors (for copy-on-write patterns)
+    "tuple": tuple,
+    "list": list,
+    "dict": dict,
+    "set": set,
+    # Simple casts if they need to normalize types
+    "int": int,
+    "float": float,
+    "str": str,
+    "bool": bool,
+    "bytes": bytes,
+    "complex": complex,
+    # Easy iteration helpers (optional but handy)
+    "range": range,
+}
+
+JSONPrimitive = Union[str, int, float, bool, None]
+JSONType = Union[JSONPrimitive, List[Any], Dict[str, Any]]  # recursive in practice

src/dabmodel/element.py

@@ -1,7 +1,7 @@
-from .meta.base import _MetaElement
+from .meta.element import _MetaElement, IElement
 
 
-class Element(metaclass=_MetaElement):
+class Element(IElement, metaclass=_MetaElement):
     """Element class
     Base class to apply metaclass and set common Fields.
     """

src/dabmodel/exception.py

@@ -4,17 +4,24 @@ class DABModelException(Exception):
     """
 
 
-class FunctionForbidden(DABModelException): ...
+class WrongUsage(DABModelException, RuntimeError):
+    pass
 
 
-class ExternalCodeForbidden(FunctionForbidden): ...
+class FunctionForbidden(DABModelException):
+    """FunctionForbidden Exception class"""
 
 
-class ClosureForbidden(FunctionForbidden): ...
+class ExternalCodeForbidden(FunctionForbidden):
+    """ExternalCodeForbidden Exception class"""
 
 
-class ReservedFieldName(Exception):
-    """DABModelException Exception class
+class ClosureForbidden(FunctionForbidden):
+    """ClosureForbidden Exception class"""
+
+
+class ReservedFieldName(AttributeError, DABModelException):
+    """ReservedFieldName Exception class
     Base Exception for DABModelException class
     """
 
@@ -31,19 +38,13 @@ class BrokenInheritance(DABModelException):
     """
 
 
-class ReadOnlyField(DABModelException):
+class ReadOnlyField(AttributeError, DABModelException):
     """ReadOnlyField Exception class
     The used Field is ReadOnly
     """
 
 
-class NewFieldForbidden(DABModelException):
-    """NewFieldForbidden Exception class
-    Field creation is forbidden
-    """
-
-
-class InvalidFieldAnnotation(DABModelException):
+class InvalidFieldAnnotation(AttributeError, DABModelException):
     """InvalidFieldAnnotation Exception class
     The field annotation is invalid
     """
@@ -67,24 +68,42 @@ class IncompletelyAnnotatedField(InvalidFieldAnnotation):
     """
 
 
-class ReadOnlyFieldAnnotation(DABModelException):
+class UnsupportedFieldType(InvalidFieldAnnotation):
+    """UnsupportedFieldType Exception class
+    The field type is unsupported
+    """
+
+
+class ReadOnlyFieldAnnotation(AttributeError, DABModelException):
     """ReadOnlyFieldAnnotation Exception class
     Field annotation connot be modified
     """
 
 
-class InvalidFieldValue(DABModelException):
+class SchemaViolation(AttributeError, DABModelException):
+    """SchemaViolation Exception class
+    The Element Schema is not respected
+    """
+
+
+class InvalidFieldValue(SchemaViolation):
     """InvalidFieldValue Exception class
     The Field value is invalid
     """
 
 
-class NonExistingField(DABModelException):
+class NonExistingField(SchemaViolation):
     """NonExistingField Exception class
     The given Field is non existing
     """
 
 
+class InvalidFieldName(AttributeError, DABModelException):
+    """InvalidFieldName Exception class
+    The Field name is invalid
+    """
+
+
 class ImportForbidden(DABModelException):
     """ImportForbidden Exception class
     Imports are forbidden
@@ -101,3 +120,27 @@ class FeatureNotBound(DABModelException):
     """FeatureNotBound Exception class
     a Feature must be bound to the appliance (or parent)
     """
+
+
+class FeatureAlreadyBound(DABModelException):
+    """FeatureAlreadyBound Exception class
+    Feature can only be bind once
+    """
+
+
+class FeatureBoundToNonAppliance(DABModelException):
+    """FeatureBoundToNonAppliance Exception class
+    Feature can only be bind to Appliance class
+    """
+
+
+class FeatureBoundToIncompatibleAppliance(DABModelException):
+    """FeatureBoundToWrongAppliance Exception class
+    Feature have to be bound to correct appliance
+    """
+
+
+class FeatureWrongBound(DABModelException):
+    """FeatureWrongBound Exception class
+    Feature can be bind to one and only one Appliance
+    """

src/dabmodel/feature.py

@@ -1,12 +1,50 @@
-from .element import Element
+from .meta.element import IFeature, IAppliance
 from .meta.feature import _MetaFeature
+from .exception import (
+    FeatureAlreadyBound,
+    FeatureNotBound,
+    FeatureBoundToNonAppliance,
+    FeatureBoundToIncompatibleAppliance,
+)
 
 
-class Feature(Element, metaclass=_MetaFeature):
+class Feature(IFeature, metaclass=_MetaFeature):
     """Feature class
     Base class for Appliance's Features.
     Features are optional traits of an appliance.
     """
 
-    _BoundAppliance: "Optional[Type[BaseAppliance]]" = None
+    __lam_bound_appliance__ = None
+
+    @classmethod
+    def check_appliance_bound(cls):
+        if cls.__lam_bound_appliance__ is None:
+            raise FeatureNotBound(f"Feature {cls} is not bound to any Appliance")
+
+    @classmethod
+    def check_appliance_compatibility(cls, appliance_cls):
+        cls.check_appliance_bound()
+
+        if not issubclass(appliance_cls, cls.__lam_bound_appliance__):
+            raise FeatureBoundToIncompatibleAppliance(
+                f"Feature {cls} is bound to an incompatible Appliance {appliance_cls}"
+            )
+
+    @classmethod
+    def bind_appliance(cls, appliance_cls):
+        if cls.__lam_bound_appliance__ is not None:
+            raise FeatureAlreadyBound(
+                f"Feature {cls} already bound to an Appliance {cls.__lam_bound_appliance__}"
+            )
+
+        if (
+            appliance_cls is None
+            or not isinstance(appliance_cls, type)
+            or not issubclass(appliance_cls, IAppliance)
+        ):
+            raise FeatureBoundToNonAppliance(
+                f"Trying to bind Feature {cls} to an invalid Appliance Reference: {appliance_cls}"
+            )
+        cls.__lam_bound_appliance__ = appliance_cls
+
     Enabled: bool = False

src/dabmodel/interfaces.py

@@ -0,0 +1,39 @@
+from typing import Generic, TypeVar, Dict, Protocol, runtime_checkable, Self
+
+
+TV_Freezable = TypeVar("TV_Freezable")
+
+
+@runtime_checkable
+class FreezableElement(Protocol, Generic[TV_Freezable]):
+
+    def clone_as_mutable_variant(self, *, deep: bool = True, _memo: Dict[int, Self] | None = None) -> Self:
+        pass
+
+    def freeze(self, force: bool = False) -> None:
+        pass
+
+    @classmethod
+    def freeze_class(cls, force: bool = False) -> None:
+        pass
+
+    def validate_schema(self) -> None:
+        pass
+
+    @classmethod
+    def validate_schema_class(cls) -> None:
+        pass
+
+    @classmethod
+    @property
+    def frozen_cls(cls) -> bool:
+        pass
+
+    @classmethod
+    @property
+    def mutable_obj(cls) -> bool:
+        pass
+
+    @property
+    def frozen(self) -> bool:
+        pass

src/dabmodel/lam_field/constraint.py

@@ -3,8 +3,8 @@ from typing import Generic, TypeVar
 T_Field = TypeVar("T_Field")
 
 
-class BaseConstraint(Generic[T_Field]):
-    """BaseConstraint class
+class Constraint(Generic[T_Field]):
+    """Constraint class
     Base class for Field's constraints
     """
 

src/dabmodel/lam_field/lam_field.py

@@ -0,0 +1,176 @@
+from typing import Generic, TypeVar, Optional, Any, Self, Annotated, get_origin, get_args
+from typeguard import check_type, CollectionCheckStrategy, TypeCheckError
+from copy import deepcopy
+from .lam_field_info import LAMFieldInfo
+from .constraint import Constraint
+from ..tools import LAMdeepfreeze
+from ..exception import InvalidFieldValue, ReadOnlyField
+from ..interfaces import FreezableElement
+
+TV_LABField = TypeVar("TV_LABField")
+
+
+class LAMField(Generic[TV_LABField]):
+    """This class describe a Field in Schema"""
+
+    def __init__(self, name: str, val: Optional[TV_LABField], ann: Any, i: LAMFieldInfo):
+        self._default_value: Optional[TV_LABField]
+        self._value: Optional[TV_LABField]
+        self.__annotations: Any
+        self.__name: str = name
+        self.__source: Optional[type] = None
+        self.__info: LAMFieldInfo = deepcopy(i)
+        self._set_annotations(ann)
+        self.__frozen: bool = False
+        self._frozen_value: Any = None
+        self.__frozen_value_set: True = False
+        self.validate(val)
+        self._init_value(val)
+
+    def _set_annotations(self, ann: Any) -> None:
+        _origin = get_origin(ann) or ann
+        _args = get_args(ann)
+
+        if _origin is Annotated:
+            self.__annotations: Any = LAMdeepfreeze(_args[0])
+        else:
+            self.__annotations: Any = LAMdeepfreeze(ann)
+
+    def _init_value(self, val: Optional[TV_LABField | FreezableElement]):
+        self._default_value: Optional[TV_LABField] = deepcopy(val)
+        self._value: Optional[TV_LABField] = val
+
+    @property
+    def name(self) -> str:
+        return self.__name
+
+    def is_frozen(self) -> bool:
+        return self.__frozen
+
+    def freeze(self):
+        self.__frozen = True
+
+    def clone_unfrozen(self) -> Self:
+        field = LAMFieldFactory.create_field(self.__name, self._default_value, self.__annotations, self.__info)
+        field.update_value(self._value)
+        return field
+
+    def add_source(self, src: type) -> None:
+        """Adds source Appliance to the Field"""
+        if self.__frozen:
+            raise ReadOnlyField("Field is frozen, cannot add source now")
+        self.__source = src
+
+    @property
+    def doc(self) -> str:
+        """Returns Field's documentation"""
+        return self.__info.doc
+
+    def add_constraint(self, cons: Constraint) -> None:
+        """Adds constraint to the Field"""
+        if self.__frozen:
+            raise ReadOnlyField("Field is frozen")
+        self.__info.add_constraint(cons)
+
+    @property
+    def constraints(self) -> list[Constraint]:
+        """Returns Field's constraint"""
+        return LAMdeepfreeze(self.__info.constraints)
+
+    def validate_self(self):
+        self.validate(self._value)
+
+    def validate(self, val: Optional[TV_LABField]):
+
+        try:
+            check_type(
+                val,
+                self.annotations,
+                collection_check_strategy=CollectionCheckStrategy.ALL_ITEMS,
+            )
+        except TypeCheckError as exp:
+            raise InvalidFieldValue(f"Value of Field <{self.__name}> is not of expected type {self.annotations}.") from exp
+
+    @property
+    def default_value(self) -> Any:
+        """Returns Field's default value (frozen)"""
+        return LAMdeepfreeze(self._default_value)
+
+    def update_value(self, val: Optional[TV_LABField] = None) -> None:
+        """Updates Field's value"""
+        if self.__frozen:
+            raise ReadOnlyField("Field is frozen")
+        self.validate(val)
+        self._value = val
+        self.__frozen_value_set = False
+
+    @property
+    def value(self) -> Any:
+        """Returns Field's value (frozen)"""
+        if self.__frozen:
+            return self.frozen_value
+        else:
+            return self.raw_value
+
+    @property
+    def raw_value(self) -> Optional[TV_LABField]:
+        """Returns Field's value"""
+        if self.__frozen:
+            raise ReadOnlyField("Field is frozen")
+        return self._value
+
+    def _generate_frozen_value(self):
+        self._frozen_value = LAMdeepfreeze(self._value)
+
+    @property
+    def frozen_value(self) -> Any:
+        if not self.__frozen_value_set:
+            self._generate_frozen_value()
+            self.__frozen_value_set = True
+        return self._frozen_value
+
+    @property
+    def annotations(self) -> Any:
+        """Returns Field's annotation"""
+        return self.__annotations
+
+    @property
+    def info(self) -> LAMFieldInfo:
+        """Returns Field's info"""
+        return self.__info
+
+
+class LAMField_Element(LAMField[FreezableElement]):
+
+    def _init_value(self, val: Optional[FreezableElement]):
+        self._default_value = deepcopy(val)
+        self._default_value.freeze()
+        self._value = val.clone_as_mutable_variant()
+
+    def validate(self, val: Optional[FreezableElement]):
+        super().validate(val)
+        if val is not None:
+            print(val)
+            val.validate_schema()
+
+    @property
+    def default_value(self) -> Any:
+        return self._default_value
+
+    def update_value(self, val: Optional[FreezableElement] = None) -> None:
+        super().update_value(val.clone_as_mutable_variant())
+
+    def _generate_frozen_value(self):
+        self._frozen_value = deepcopy(self._value)
+        self._frozen_value.freeze()
+
+
+class LAMFieldFactory:
+    @staticmethod
+    def create_field(name: str, val: Optional[TV_LABField], anno: Any, info: LAMFieldInfo) -> LAMField:
+        if isinstance(val, FreezableElement):
+            print(f"Spawn LAMField_Element {name} !!!")
+            return LAMField_Element(name, val, anno, info)
+        else:
+            print(f"Spawn LAMField {name} !!!")
+            return LAMField(name, val, anno, info)

src/dabmodel/lam_field/lam_field_info.py

@@ -0,0 +1,27 @@
+from typing import Optional, Any
+from .constraint import Constraint
+
+
+class LAMFieldInfo:
+    """This Class allows to describe a Field in Appliance class"""
+
+    def __init__(self, *, doc: str = "", constraints: Optional[list[Constraint]] = None):
+        self.__doc: str = doc
+        self.__constraints: list[Constraint]
+        if constraints is None:
+            self.__constraints = []
+        else:
+            self.__constraints = constraints
+
+    def add_constraint(self, constraint: Constraint):
+        self.__constraints.append(constraint)
+
+    @property
+    def doc(self) -> str:
+        """Returns Field's documentation"""
+        return self.__doc
+
+    @property
+    def constraints(self) -> list[Constraint[Any]]:
+        """Returns Field's constraints"""
+        return self.__constraints

src/dabmodel/meta/appliance.py

@@ -1,18 +1,10 @@
 from typing import Any, Type
+from frozendict import frozendict
 from copy import copy
 
-from typeguard import check_type, CollectionCheckStrategy, TypeCheckError
-
-from ..tools import LAMdeepfreeze
-from ..LAMFields.LAMField import LAMField
-from ..LAMFields.FrozenLAMField import FrozenLAMField
-from .base import _MetaElement
+from .element import _MetaElement, get_mutable_variant
 from ..feature import Feature
-from ..exception import (
-    InvalidFieldValue,
-    InvalidFeatureInheritance,
-    FeatureNotBound,
-)
+from ..exception import InvalidFieldValue, InvalidFeatureInheritance, InvalidFieldName
 
 
 class _MetaAppliance(_MetaElement):
@@ -26,20 +18,30 @@ class _MetaAppliance(_MetaElement):
         name: str,
         bases: tuple[type[Any], ...],
         namespace: dict[str, Any],  # pylint: disable=unused-argument
-        extensions: dict[str, Any],
+        stack_exts: dict[str, Any],
     ) -> None:
         """
         Appliance-specific pre-check: ensure the `features` slot exists in schema.
 
         Copies the parent's `features` mapping when inheriting to keep it per-class.
         """
-        super().check_class(name, bases, namespace, extensions)  # type: ignore[misc]
-        if "features" not in namespace["__DABSchema__"]:
-            namespace["__DABSchema__"]["features"] = {}
-        else:
-            namespace["__DABSchema__"]["features"] = copy(
-                namespace["__DABSchema__"]["features"]
-            )
+
+        super().check_class(name, bases, namespace, stack_exts)  # type: ignore[misc]
+
+        if "features" not in namespace["__lam_schema__"]:
+            namespace["__lam_schema__"]["features"] = {}
+
+    @classmethod
+    def inherit_schema(  # pylint: disable=too-complex,too-many-branches
+        mcs: type["_MetaElement"],
+        name: str,
+        base: type[Any],
+        namespace: dict[str, Any],
+        stack_exts: dict[str, Any],
+    ):
+        super().inherit_schema(name, base, namespace, stack_exts)
+        if "features" in base.__lam_schema__:
+            namespace["__lam_schema__"]["features"] = dict(base.__lam_schema__["features"])
 
     @classmethod
     def process_class_fields(
@@ -47,18 +49,18 @@ class _MetaAppliance(_MetaElement):
         name: str,
         bases: tuple[type[Any], ...],
         namespace: dict[str, Any],
-        extensions: dict[str, Any],
+        stack_exts: dict[str, Any],
     ):
         """
         Like meta.process_class_fields but also stages Feature declarations.
 
         Initializes:
-          extensions["new_features"], extensions["modified_features"]
+          stack_exts["new_features"], stack_exts["modified_features"]
         then defers to the base scanner for regular fields.
         """
-        extensions["new_features"] = {}
-        extensions["modified_features"] = {}
-        super().process_class_fields(name, bases, namespace, extensions)  # type: ignore[misc]
+        stack_exts["new_features"] = {}
+        stack_exts["modified_features"] = {}
+        super().process_class_fields(name, bases, namespace, stack_exts)  # type: ignore[misc]
 
     @classmethod
     def process_new_field(
@@ -68,7 +70,7 @@ class _MetaAppliance(_MetaElement):
         namespace: dict[str, Any],
         _fname: str,
         _fvalue: Any,
-        extensions: dict[str, Any],
+        stack_exts: dict[str, Any],
     ):  # pylint: disable=unused-argument
         """
         Intercept Feature declarations.
@@ -78,16 +80,19 @@ class _MetaAppliance(_MetaElement):
         - Else, if `_fvalue` is a Feature *class*, stage into `new_features`.
         - Otherwise, it is a regular field: delegate to meta.process_new_field.
         """
-        if _fname in namespace["__DABSchema__"]["features"].keys():
-            if not issubclass(_fvalue, namespace["__DABSchema__"]["features"][_fname]):
-                raise InvalidFeatureInheritance(
-                    f"Feature {_fname} is not an instance of {bases[0]}.{_fname}"
-                )
-            extensions["modified_features"][_fname] = _fvalue
+
+        if _fname == "features":
+            raise InvalidFieldName("'feature' is a reserved Field name")
+        if _fname in namespace["__lam_schema__"]["features"]:
+            if not issubclass(_fvalue, namespace["__lam_schema__"]["features"][_fname]):
+                raise InvalidFeatureInheritance(f"Feature {_fname} is not a subclass of {bases[0]}.{_fname}")
+            stack_exts["modified_features"][_fname] = get_mutable_variant(_fvalue)
+            namespace[_fname] = stack_exts["modified_features"][_fname]
         elif isinstance(_fvalue, type) and issubclass(_fvalue, Feature):
-            extensions["new_features"][_fname] = _fvalue
+            stack_exts["new_features"][_fname] = get_mutable_variant(_fvalue)
+            namespace[_fname] = stack_exts["new_features"][_fname]
         else:
-            super().process_new_field(name, bases, namespace, _fname, _fvalue, extensions)  # type: ignore[misc]
+            super().process_new_field(name, bases, namespace, _fname, _fvalue, stack_exts)  # type: ignore[misc]
 
     @classmethod
     def commit_fields(
@@ -96,71 +101,72 @@ class _MetaAppliance(_MetaElement):
         name: str,
         bases: tuple[type[Any], ...],
         namespace: dict[str, Any],  # pylint: disable=unused-argument
-        extensions: dict[str, Any],
+        stack_exts: dict[str, Any],
     ):
         """
         Commit regular fields (via meta) and then bind staged Feature classes.
 
         For each new/modified feature:
           - bind it to `cls` (sets the feature's `_BoundAppliance`),
-          - register it under `cls.__DABSchema__["features"]`.
+          - register it under `cls.__LAMSchema__["features"]`.
         """
-        super().commit_fields(cls, name, bases, namespace, extensions)  # type: ignore[misc]
+        super().commit_fields(cls, name, bases, namespace, stack_exts)  # type: ignore[misc]
 
-        for _ftname, _ftvalue in extensions["modified_features"].items():
-            _ftvalue._BoundAppliance = cls  # pylint: disable=protected-access
-            cls.__DABSchema__["features"][_ftname] = _ftvalue
-        for _ftname, _ftvalue in extensions["new_features"].items():
-            _ftvalue._BoundAppliance = cls  # pylint: disable=protected-access
-            cls.__DABSchema__["features"][_ftname] = _ftvalue
+        cls.__lam_schema__["features"].update(stack_exts["modified_features"])
+        for v in stack_exts["new_features"].values():
+            v.bind_appliance(cls)
+        cls.__lam_schema__["features"].update(stack_exts["new_features"])
 
-    def finalize_instance(cls: Type, obj, extensions: dict[str, Any]):
-        """
-        Instantiate and attach all features declared (or overridden) in the instance schema.
-        Handles:
-          - Declared features (plain class)
-          - Subclass replacements
-          - Dict overrides (class + patch dict)
-        """
-        for fname, fdef in obj.__DABSchema__.get("features", {}).items():
-            # Case 1: plain class or subclass
-            if isinstance(fdef, type) and issubclass(fdef, Feature):
-                inst = fdef()
-                object.__setattr__(obj, fname, inst)
+    @classmethod
+    def prepare_initializer_fields(
+        mcs: type["_MetaElement"],
+        cls,
+        name: str,
+        bases: tuple[type[Any], ...],
+        namespace: dict[str, Any],  # pylint: disable=unused-argument
+        init_fieldvalues: dict[str, Any],
+        init_fieldtypes: dict[str, Any],
+        stack_exts: dict[str, Any],
+    ):
+        for k, v in cls.__lam_schema__["features"].items():
+            init_fieldvalues[k] = v
+            init_fieldtypes[k] = v
 
-            # Case 2: (class, dict) → dict overrides
-            elif isinstance(fdef, tuple) and len(fdef) == 2:
-                feat_cls, overrides = fdef
-                inst = feat_cls()
-                for field_name, new_val in overrides.items():
-                    if field_name not in feat_cls.__DABSchema__:
-                        raise InvalidFieldValue(
-                            f"Feature '{fname}' has no field '{field_name}'"
-                        )
-                    field = feat_cls.__DABSchema__[field_name]
-                    try:
-                        check_type(
-                            new_val,
-                            field.annotations,
-                            collection_check_strategy=CollectionCheckStrategy.ALL_ITEMS,
-                        )
-                    except TypeCheckError as exp:
-                        raise InvalidFieldValue(
-                            f"Invalid value for {fname}.{field_name}: "
-                            f"expected {field.annotations}, got {new_val!r}"
-                        ) from exp
-                    object.__setattr__(inst, field_name, LAMdeepfreeze(new_val))
-                    inst.__DABSchema__[field_name] = FrozenLAMField(
-                        LAMField(field_name, new_val, field.annotations, field._info)
-                    )
-                object.__setattr__(obj, fname, inst)
+    @classmethod
+    def commit_initializer_fields(
+        mcs: type["_MetaElement"],
+        cls,
+        name: str,
+        bases: tuple[type[Any], ...],
+        namespace: dict[str, Any],  # pylint: disable=unused-argument
+        fakecls_exports: dict[str, Any],
+        stack_exts: dict[str, Any],
+    ):
+        for fk, fv in cls.__lam_schema__["features"].items():
+            for k, v in fv.__lam_schema__.items():
+                v.update_value(fakecls_exports[fk].__getattr__(k))
 
-            else:
-                raise InvalidFieldValue(
-                    f"Invalid feature definition stored for '{fname}': {fdef!r}"
-                )
+    @classmethod
+    def finalize_class(
+        mcs: type["_MetaElement"],
+        cls,
+        name: str,
+        bases: tuple[type[Any], ...],
+        namespace: dict[str, Any],  # pylint: disable=unused-argument
+        stack_exts: dict[str, Any],
+    ):
+        cls.__lam_schema__["features"] = frozendict(cls.__lam_schema__["features"])
 
-    def apply_overrides(cls, obj, extensions, *args, **kwargs):
+        super().finalize_class(cls, name, bases, namespace, stack_exts)
+        if not cls.__lam_class_mutable__:
+            for feat in cls.__lam_schema__["features"].values():
+                feat.freeze_class(True)
+
+    def populate_instance(cls: Type, obj: Any, stack_exts: dict[str, Any], *args: Any, **kw: Any):
+        super().populate_instance(obj, stack_exts, *args, **kw)
+        obj.__lam_schema__["features"] = dict(cls.__lam_schema__["features"])
+
+    def apply_overrides(cls, obj, stack_exts, *args, **kwargs):
         """
         Support for runtime field and feature overrides.
 
@@ -171,65 +177,66 @@ class _MetaAppliance(_MetaElement):
           MyApp(F1=MyF1)                # inheritance / replacement
           MyApp(F1={"val": 42, ...})    # dict override of existing feature
         """
-        # --- field overrides (unchanged) ---
-        for k, v in list(kwargs.items()):
-            if k in cls.__DABSchema__:  # regular field
-                field = cls.__DABSchema__[k]
-                try:
-                    check_type(
-                        v,
-                        field.annotations,
-                        collection_check_strategy=CollectionCheckStrategy.ALL_ITEMS,
-                    )
-                except TypeCheckError as exp:
-                    raise InvalidFieldValue(
-                        f"Invalid value for field '{k}': expected {field.annotations}, got {v!r}"
-                    ) from exp
-
-                object.__setattr__(obj, k, LAMdeepfreeze(v))
-                obj.__DABSchema__[k] = FrozenLAMField(
-                    LAMField(k, v, field.annotations, field._info)
-                )
-                kwargs.pop(k)
 
         # --- feature overrides ---
         for k, v in list(kwargs.items()):
-            if k in cls.__DABSchema__.get("features", {}):
-                base_feat_cls = cls.__DABSchema__["features"][k]
+            if k in obj.__lam_schema__["features"]:
+                base_feat_cls = obj.__lam_schema__["features"][k]
 
                 # Case 1: subclass replacement (inheritance)
                 if isinstance(v, type) and issubclass(v, base_feat_cls):
-                    bound = getattr(v, "_BoundAppliance", None)
-                    if bound is None or not issubclass(cls, bound):
-                        raise FeatureNotBound(
-                            f"Feature {v.__name__} is not bound to {cls.__name__}"
-                        )
+                    v.check_appliance_compatibility(cls)
+
                     # record subclass into instance schema
-                    obj.__DABSchema__["features"][k] = v
+                    obj.__lam_schema__["features"][k] = get_mutable_variant(v)
+                    if not obj.__lam_class_mutable__:
+                        obj.__lam_schema__["features"][k].freeze_class(True)
                     kwargs.pop(k)
 
                 # Case 2: dict override
                 elif isinstance(v, dict):
                     # store (class, override_dict) for finalize_instance
-                    obj.__DABSchema__["features"][k] = (base_feat_cls, v)
+                    obj.__lam_schema__["features"][k] = (base_feat_cls, v)
                     kwargs.pop(k)
 
                 else:
-                    raise InvalidFieldValue(
-                        f"Feature override for '{k}' must be a Feature subclass or dict, got {type(v)}"
-                    )
+                    raise InvalidFieldValue(f"Feature override for '{k}' must be a Feature subclass or dict, got {type(v)}")
 
         # --- new features not declared at class level ---
         for k, v in list(kwargs.items()):
             if isinstance(v, type) and issubclass(v, Feature):
-                bound = getattr(v, "_BoundAppliance", None)
-                if bound is None or not issubclass(cls, bound):
-                    raise FeatureNotBound(
-                        f"Feature {v.__name__} is not bound to {cls.__name__}"
-                    )
-                obj.__DABSchema__["features"][k] = v
+                v.check_appliance_compatibility(cls)
+                obj.__lam_schema__["features"][k] = get_mutable_variant(v)
+                if not obj.__lam_class_mutable__:
+                    obj.__lam_schema__["features"][k].freeze_class(True)
                 kwargs.pop(k)
 
-        if kwargs:
-            unknown = ", ".join(sorted(kwargs.keys()))
-            raise InvalidFieldValue(f"Unknown parameters: {unknown}")
+        super().apply_overrides(obj, stack_exts, *args, **kwargs)
+
+    def finalize_instance(cls: Type, obj, stack_exts: dict[str, Any]):
+        """
+        Instantiate and attach all features declared (or overridden) in the instance schema.
+        Handles:
+          - Declared features (plain class)
+          - Subclass replacements
+          - Dict overrides (class + patch dict)
+        """
+
+        for k, v in obj.__lam_schema__["features"].items():
+            # Case 1: plain class or subclass
+            if isinstance(v, type) and issubclass(v, Feature):
+                inst = v()
+                object.__setattr__(obj, k, inst)
+
+            # Case 2: (class, dict) → dict overrides
+            elif isinstance(v, tuple) and len(v) == 2:
+                feat_cls, overrides = v
+                inst = feat_cls(**overrides)
+                object.__setattr__(obj, k, inst)
+                obj.__lam_schema__["features"][k] = feat_cls
+
+            else:
+                raise InvalidFieldValue(f"Invalid feature definition stored for '{k}': {fdef!r}")
+
+        obj.__lam_schema__["features"] = frozendict(obj.__lam_schema__["features"])
+        super().finalize_instance(obj, stack_exts)

src/dabmodel/meta/base.py

@@ -1,749 +0,0 @@
-from typing import (
-    Optional,
-    TypeVar,
-    Union,
-    get_origin,
-    get_args,
-    List,
-    Dict,
-    Any,
-    Tuple,
-    Set,
-    Annotated,
-    FrozenSet,
-    Callable,
-    Type,
-)
-
-from types import UnionType, FunctionType, SimpleNamespace
-from copy import deepcopy, copy
-
-import math
-import inspect, ast, textwrap
-
-from typeguard import check_type, TypeCheckError, CollectionCheckStrategy
-
-from ..LAMFields.LAMField import LAMField
-from ..LAMFields.LAMFieldInfo import LAMFieldInfo
-from ..LAMFields.FrozenLAMField import FrozenLAMField
-
-from ..exception import (
-    MultipleInheritanceForbidden,
-    BrokenInheritance,
-    ReadOnlyField,
-    NewFieldForbidden,
-    NotAnnotatedField,
-    ReadOnlyFieldAnnotation,
-    InvalidFieldValue,
-    InvalidFieldAnnotation,
-    IncompletelyAnnotatedField,
-    ImportForbidden,
-    FunctionForbidden,
-    NonExistingField,
-    InvalidInitializerType,
-)
-
-ALLOWED_ANNOTATIONS: dict[str, Any] = {
-    "Union": Union,
-    "Optional": Optional,
-    "List": List,
-    "Dict": Dict,
-    "Tuple": Tuple,
-    "Set": Set,
-    "FrozenSet": FrozenSet,
-    "Annotated": Annotated,
-    # builtins:
-    "int": int,
-    "str": str,
-    "float": float,
-    "bool": bool,
-    "complex": complex,
-    "bytes": bytes,
-    "None": type(None),
-    "list": list,
-    "dict": dict,
-    "set": set,
-    "frozenset": frozenset,
-    "tuple": tuple,
-}
-ALLOWED_MODEL_FIELDS_TYPES: tuple[type[Any], ...] = (
-    str,
-    int,
-    float,
-    complex,
-    bool,
-    bytes,
-)
-
-
-ALLOWED_HELPERS_MATH = SimpleNamespace(
-    sqrt=math.sqrt,
-    floor=math.floor,
-    ceil=math.ceil,
-    trunc=math.trunc,
-    fabs=math.fabs,
-    copysign=math.copysign,
-    hypot=math.hypot,
-    exp=math.exp,
-    log=math.log,
-    log10=math.log10,
-    sin=math.sin,
-    cos=math.cos,
-    tan=math.tan,
-    atan2=math.atan2,
-    radians=math.radians,
-    degrees=math.degrees,
-)
-
-ALLOWED_HELPERS_DEFAULT: dict[str, object] = {
-    "math": ALLOWED_HELPERS_MATH,
-    "print": print,
-    # Numbers & reducers (pure, deterministic)
-    "abs": abs,
-    "round": round,
-    "min": min,
-    "max": max,
-    "sum": sum,
-    # Introspection-free basics
-    "len": len,
-    "sorted": sorted,
-    # Basic constructors (for copy-on-write patterns)
-    "tuple": tuple,
-    "list": list,
-    "dict": dict,
-    "set": set,
-    # Simple casts if they need to normalize types
-    "int": int,
-    "float": float,
-    "str": str,
-    "bool": bool,
-    "bytes": bytes,
-    "complex": complex,
-    # Easy iteration helpers (optional but handy)
-    "range": range,
-}
-
-
-def _check_initializer_safety(func) -> None:
-    """
-    Preliminary structural check for __initializer__.
-
-    Policy (minimal):
-      - Forbid 'import' / 'from ... import ...' inside the initializer body.
-      - Forbid nested function definitions (closures/helpers) in the body.
-      - Allow lambdas.
-      - No restrictions on calls here (keep it simple).
-      - Optionally forbid closures (free vars) for determinism.
-    """
-    try:
-        src = inspect.getsource(func)
-    except OSError as exc:
-        # If source isn't available (rare), fail closed (or skip if you prefer)
-        raise FunctionForbidden("Cannot inspect __initializer__ source") from exc
-
-    src = textwrap.dedent(src)
-    mod = ast.parse(src)
-
-    # Find the FunctionDef node that corresponds to this initializer
-    init_node = None
-    for n in mod.body:
-        if (
-            isinstance(n, (ast.FunctionDef, ast.AsyncFunctionDef))
-            and n.name == func.__name__
-        ):
-            init_node = n
-            break
-    if init_node is None:
-        # Fallback: if not found, analyze nothing further to avoid false positives
-        return
-
-    # Walk ONLY the body of the initializer (don't flag the def itself)
-    body_tree = ast.Module(body=init_node.body, type_ignores=[])
-
-    for node in ast.walk(body_tree):
-        # Forbid imports
-        if isinstance(node, (ast.Import, ast.ImportFrom)):
-            raise ImportForbidden("imports disabled in __initializer")
-
-        # Forbid nested defs (but allow lambdas)
-        if isinstance(node, (ast.FunctionDef, ast.AsyncFunctionDef)):
-            raise FunctionForbidden(
-                "Nested function definitions are forbidden in __initializer"
-            )
-
-        if isinstance(node, ast.Lambda):  # Forbid lambda
-            raise FunctionForbidden("Lambdas are forbidden in __initializer")
-
-    # Optional: forbid closures (keeps determinism; allows lambdas that don't capture)
-    if func.__code__.co_freevars:
-        raise FunctionForbidden("Closures are forbidden in __initializer__")
-
-
-def _blocked_import(*args, **kwargs):
-    raise ImportForbidden("imports disabled in __initializer")
-
-
-def _resolve_annotation(ann):
-    if isinstance(ann, str):
-        # Safe eval against a **whitelist** only
-        return eval(  # pylint: disable=eval-used
-            ann, {"__builtins__": {}}, ALLOWED_ANNOTATIONS
-        )
-    return ann
-
-
-def _peel_annotated(t: Any) -> Any:
-    # If you ever allow Annotated[T, ...], peel to T
-    while True:
-        origin = get_origin(t)
-        if origin is None:
-            return t
-        name = (
-            getattr(origin, "__name__", "")
-            or getattr(origin, "__qualname__", "")
-            or str(origin)
-        )
-        if "Annotated" in name:
-            args = get_args(t)
-            t = args[0] if args else t
-        else:
-            return t
-
-
-def _check_annotation_definition(  # pylint: disable=too-complex,too-many-return-statements
-    _type,
-) -> bool:
-    _type = _peel_annotated(_type)
-    # handle Optional[] and Union[None,...]
-    if (get_origin(_type) is Union or get_origin(_type) is UnionType) and type(
-        None
-    ) in get_args(_type):
-        return all(
-            _check_annotation_definition(_)
-            for _ in get_args(_type)
-            if _ is not type(None)
-        )
-
-    # handle other Union[...]
-    if get_origin(_type) is Union or get_origin(_type) is UnionType:
-        return all(_check_annotation_definition(_) for _ in get_args(_type))
-
-    # handle Dict[...]
-    if get_origin(_type) is dict:
-        inner = get_args(_type)
-        if len(inner) != 2:
-            raise IncompletelyAnnotatedField(
-                f"Dict Annotation requires 2 inner definitions: {_type}"
-            )
-        return _peel_annotated(
-            inner[0]
-        ) in ALLOWED_MODEL_FIELDS_TYPES and _check_annotation_definition(inner[1])
-
-    # handle Tuple[]
-    if get_origin(_type) in [tuple]:
-        inner_types = get_args(_type)
-        if len(inner_types) == 0:
-            raise IncompletelyAnnotatedField(
-                f"Annotation requires inner definition: {_type}"
-            )
-        if len(inner_types) == 2 and inner_types[1] is Ellipsis:
-            return _check_annotation_definition(inner_types[0])
-        return all(_check_annotation_definition(_) for _ in inner_types)
-
-    # handle Set[],Tuple[],FrozenSet[],List[]
-    if get_origin(_type) in [set, frozenset, tuple, list]:
-        inner_types = get_args(_type)
-        if len(inner_types) == 0:
-            raise IncompletelyAnnotatedField(
-                f"Annotation requires inner definition: {_type}"
-            )
-        return all(_check_annotation_definition(_) for _ in inner_types)
-
-    if _type in ALLOWED_MODEL_FIELDS_TYPES:
-        return True
-    return False
-
-
-class ModelSpecView:
-    """ModelSpecView class
-    A class that will act as fake BaseElement proxy to allow setting values"""
-
-    __slots__ = ("_vals", "_types", "_touched", "_name", "_module")
-
-    def __init__(
-        self, values: dict[str, Any], types_map: dict[str, type], name: str, module: str
-    ):
-        self._name: str
-        self._vals: dict[str, Any]
-        self._types: dict[str, type]
-        self._touched: set
-        self._module: str
-        object.__setattr__(self, "_vals", dict(values))
-        object.__setattr__(self, "_types", types_map)
-        object.__setattr__(self, "_name", name)
-        object.__setattr__(self, "_module", module)
-
-    @property
-    def __name__(self) -> str:
-        """returns proxified class' name"""
-        return self._name
-
-    @property
-    def __module__(self) -> str:
-        """returns proxified module's name"""
-        return self._module
-
-    @__module__.setter
-    def __module__(self, value: str):
-        pass
-
-    def __getattr__(self, name: str) -> Any:
-        """internal proxy getattr"""
-        if name not in self._types:
-            raise AttributeError(f"Unknown field {name}")
-        return self._vals[name]
-
-    def __setattr__(self, name: str, value: Any):
-        """internal proxy setattr"""
-        if name not in self._types:
-            raise NonExistingField(f"Cannot set unknown field {name}")
-        T = self._types[name]
-
-        try:
-            check_type(
-                value,
-                T,
-                collection_check_strategy=CollectionCheckStrategy.ALL_ITEMS,
-            )
-        except TypeCheckError as exp:
-            raise InvalidFieldValue(
-                f"Field <{name}> value is not of expected type {T}."
-            ) from exp
-
-        self._vals[name] = value
-
-    def export(self) -> dict:
-        """exports all proxified values"""
-        return dict(self._vals)
-
-
-T_Meta = TypeVar("T_Meta", bound="_MetaElement")
-T_BE = TypeVar("T_BE", bound="BaseElement")
-
-
-class _MetaElement(type):
-    """metaclass to use to build BaseElement"""
-
-    modified_fields: Dict[str, Any] = {}
-    new_fields: Dict[str, LAMField[Any]] = {}
-    initializer: Optional[Callable[..., Any]] = None
-    __DABSchema__: dict[str, Any] = {}
-
-    @classmethod
-    def check_class(
-        mcs: type["_MetaElement"],
-        name: str,
-        bases: tuple[type[Any], ...],
-        namespace: dict[str, Any],  # pylint: disable=unused-argument
-        extensions: dict[str, Any],
-    ) -> None:
-        """
-        Early class-build hook.
-
-        Validates the inheritance shape, initializes an empty schema for root classes,
-        copies the parent schema for subclasses, and ensures all annotated fields
-        have a default (inserting `None` when missing).
-
-        This runs before the class object is created.
-        """
-        # print("__NEW__ Defining:", name, "with keys:", list(namespace))
-
-        if len(bases) > 1:
-            raise MultipleInheritanceForbidden(
-                "Multiple inheritance is not supported by dabmodel"
-            )
-        if len(bases) == 0:  # base class (BaseElement)
-            namespace["__DABSchema__"] = {}
-        else:  # standard inheritance
-            # check class tree origin
-            if "__DABSchema__" not in dir(bases[0]):
-                raise BrokenInheritance(
-                    "__DABSchema__ not found in base class, broken inheritance chain."
-                )
-            # copy inherited schema
-            namespace["__DABSchema__"] = copy(bases[0].__DABSchema__)
-
-        # force field without default value to be instantiated (with None)
-        if "__annotations__" in namespace:
-            for _funknown in [
-                _ for _ in namespace["__annotations__"] if _ not in namespace.keys()
-            ]:
-                namespace[_funknown] = None
-
-    @classmethod
-    def process_class_fields(  # pylint: disable=too-complex,too-many-branches
-        mcs: type["_MetaElement"],
-        name: str,
-        bases: tuple[type[Any], ...],
-        namespace: dict[str, Any],
-        extensions: dict[str, Any],
-    ):
-        """
-        Scan the class namespace and partition fields.
-
-        Detects:
-          - modified fields (shadowing parent values),
-          - new fields (present in annotations),
-          - the optional `__initializer` classmethod (in mangled or unmangled form).
-
-        Validates annotations and types and removes processed items from `namespace`
-        so they won't become normal attributes. Results are staged into:
-          mcs.new_fields, mcs.modified_fields, mcs.initializer
-        to be committed later.
-        """
-        # iterating new and modified fields
-        mcs.modified_fields = {}
-        mcs.new_fields = {}
-        mcs.initializer = None
-        initializer_name: Optional[str] = None
-        for _fname, _fvalue in namespace.items():
-            if _fname == f"_{name}__initializer" or (
-                name.startswith("_") and _fname == "__initializer"
-            ):
-                if not isinstance(_fvalue, classmethod):
-                    raise InvalidInitializerType()
-                mcs.initializer = _fvalue.__func__
-                if name.startswith("_"):
-                    initializer_name = "__initializer"
-                else:
-                    initializer_name = f"_{name}__initializer"
-            elif _fname.startswith("_"):
-                pass
-            elif isinstance(_fvalue, classmethod):
-                pass
-            else:
-                print(f"Parsing Field: {_fname} / {_fvalue}")
-                if (
-                    len(bases) == 1 and _fname in namespace["__DABSchema__"].keys()
-                ):  # Modified fields
-                    mcs.process_modified_field(
-                        name, bases, namespace, _fname, _fvalue, extensions
-                    )
-                else:  # New fieds
-                    mcs.process_new_field(
-                        name, bases, namespace, _fname, _fvalue, extensions
-                    )
-        # removing modified fields from class (will add them back later)
-        for _fname in mcs.new_fields:
-            del namespace[_fname]
-        for _fname in mcs.modified_fields:
-            del namespace[_fname]
-        if mcs.initializer is not None and initializer_name is not None:
-            del namespace[initializer_name]
-
-    @classmethod
-    def process_modified_field(
-        mcs: type["_MetaElement"],
-        name: str,
-        bases: tuple[type[Any], ...],
-        namespace: dict[str, Any],
-        _fname: str,
-        _fvalue: Any,
-        extensions: dict[str, Any],
-    ):  # pylint: disable=unused-argument
-        """
-        Handle a *modified* field declared by a subclass.
-
-        Forbids annotation changes, validates the new default value against
-        the inherited annotation, and stages the new default into `mcs.modified_fields`.
-        """
-        if "__annotations__" in namespace and _fname in namespace["__annotations__"]:
-            raise ReadOnlyFieldAnnotation(
-                f"annotations cannot be modified on derived classes {_fname}"
-            )
-        try:
-            check_type(
-                _fvalue,
-                namespace["__DABSchema__"][_fname].annotations,
-                collection_check_strategy=CollectionCheckStrategy.ALL_ITEMS,
-            )
-        except TypeCheckError as exp:
-            raise InvalidFieldValue(
-                f"Field <{_fname}> New Field value is not of expected type {bases[0].__annotations__[_fname]}."
-            ) from exp
-        mcs.modified_fields[_fname] = _fvalue
-
-    @classmethod
-    def process_new_field(
-        mcs: type["_MetaElement"],
-        name: str,
-        bases: tuple[type[Any], ...],
-        namespace: dict[str, Any],
-        _fname: str,
-        _fvalue: Any,
-        extensions: dict[str, Any],
-    ):  # pylint: disable=unused-argument
-        """
-        Handle a *new* field declared on the class.
-
-        Resolves string annotations against a whitelist, validates `Annotated[...]`
-        payloads (allowing only LAMFieldInfo), checks the default value type,
-        and stages the field as a `LAMField` in `mcs.new_fields`.
-        """
-        # print(f"New field: {_fname}")
-
-        # check if field is annotated
-        if (
-            "__annotations__" not in namespace
-            or _fname not in namespace["__annotations__"]
-        ):
-            raise NotAnnotatedField(
-                f"Every dabmodel Fields must be annotated ({_fname})"
-            )
-
-        # check if annotation is allowed
-        if isinstance(namespace["__annotations__"][_fname], str):
-            namespace["__annotations__"][_fname] = _resolve_annotation(
-                namespace["__annotations__"][_fname]
-            )
-
-        if not _check_annotation_definition(namespace["__annotations__"][_fname]):
-            raise InvalidFieldAnnotation(
-                f"Field <{_fname}> has not an allowed or valid annotation."
-            )
-
-        _finfo: LAMFieldInfo = LAMFieldInfo()
-        origin = get_origin(namespace["__annotations__"][_fname])
-        tname = (
-            getattr(origin, "__name__", "")
-            or getattr(origin, "__qualname__", "")
-            or str(origin)
-        )
-        if "Annotated" in tname:
-            args = get_args(namespace["__annotations__"][_fname])
-            if args:
-                if len(args) > 2:
-                    raise InvalidFieldAnnotation(
-                        f"Field <{_fname}> had invalid Annotated value."
-                    )
-                if len(args) == 2 and not isinstance(args[1], LAMFieldInfo):
-                    raise InvalidFieldAnnotation(
-                        "Only LAMFieldInfo object is allowed as Annotated data."
-                    )
-
-                _finfo = args[1]
-
-        # check if value is valid
-        try:
-            check_type(
-                _fvalue,
-                namespace["__annotations__"][_fname],
-                collection_check_strategy=CollectionCheckStrategy.ALL_ITEMS,
-            )
-        except TypeCheckError as exp:
-            raise InvalidFieldValue(
-                f"Value of Field <{_fname}> is not of expected type {namespace['__annotations__'][_fname]}."
-            ) from exp
-        mcs.new_fields[_fname] = LAMField(
-            _fname, _fvalue, namespace["__annotations__"][_fname], _finfo
-        )
-
-    @classmethod
-    def apply_initializer(
-        mcs: type["_MetaElement"],
-        cls,
-        name: str,
-        bases: tuple[type[Any], ...],
-        namespace: dict[str, Any],  # pylint: disable=unused-argument
-        extensions: dict[str, Any],
-    ):
-        """
-        Apply the optional `__initializer` classmethod to compute derived defaults.
-
-        The initializer runs in a restricted, import-blocked environment using a
-        `ModelSpecView` proxy that enforces type checking on assignments.
-        On success, the computed values are validated and written back into the
-        class schema's DABFields.
-        """
-        if mcs.initializer is not None:
-            _check_initializer_safety(mcs.initializer)
-            init_fieldvalues = {}
-            init_fieldtypes = {}
-            for _fname, _fvalue in cls.__DABSchema__.items():
-                if isinstance(_fvalue, LAMField):
-                    init_fieldvalues[_fname] = deepcopy(_fvalue.raw_value)
-                    init_fieldtypes[_fname] = _fvalue.annotations
-            fakecls = ModelSpecView(
-                init_fieldvalues, init_fieldtypes, cls.__name__, cls.__module__
-            )
-            safe_globals = {
-                "__builtins__": {"__import__": _blocked_import},
-                **ALLOWED_HELPERS_DEFAULT,
-            }
-            if mcs.initializer.__code__.co_freevars:
-                raise FunctionForbidden("__initializer must not use closures")
-            safe_initializer = FunctionType(
-                mcs.initializer.__code__,
-                safe_globals,
-                name=mcs.initializer.__name__,
-                argdefs=mcs.initializer.__defaults__,
-                closure=None,
-            )
-            safe_initializer(fakecls)  # pylint: disable=not-callable
-            for _fname, _fvalue in fakecls.export().items():
-                try:
-                    check_type(
-                        _fvalue,
-                        cls.__DABSchema__[_fname].annotations,
-                        collection_check_strategy=CollectionCheckStrategy.ALL_ITEMS,
-                    )
-                except TypeCheckError as exp:
-                    raise InvalidFieldValue(
-                        f"Value of Field <{_fname}> is not of expected type {namespace['__annotations__'][_fname]}."
-                    ) from exp
-                cls.__DABSchema__[_fname].update_value(_fvalue)
-
-    def __new__(
-        mcs: type["_MetaElement"],
-        name: str,
-        bases: tuple[type[Any], ...],
-        namespace: dict[str, Any],
-    ) -> Type:
-        """BaseElement new class"""
-        extensions: dict[str, Any] = {}
-        mcs.check_class(name, bases, namespace, extensions)
-        mcs.process_class_fields(name, bases, namespace, extensions)
-
-        _cls = super().__new__(mcs, name, bases, namespace)
-
-        mcs.commit_fields(_cls, name, bases, namespace, extensions)
-        mcs.apply_initializer(_cls, name, bases, namespace, extensions)
-        _cls.install_instance_guard(extensions)
-
-        return _cls
-
-    @classmethod
-    def commit_fields(
-        mcs: type["_MetaElement"],
-        cls,
-        name: str,
-        bases: tuple[type[Any], ...],
-        namespace: dict[str, Any],  # pylint: disable=unused-argument
-        extensions: dict[str, Any],
-    ):
-        """
-        Commit staged fields into the class schema (`__DABSchema__`).
-
-        - For modified fields: copy the parent's LAMField, update its value.
-        - For new fields: set the freshly built LAMField and record its source.
-        """
-        for _fname, _fvalue in mcs.modified_fields.items():
-            cls.__DABSchema__[_fname] = deepcopy(bases[0].__DABSchema__[_fname])
-            cls.__DABSchema__[_fname].update_value(_fvalue)
-
-        for _fname, _fvalue in mcs.new_fields.items():
-            _fvalue.add_source(cls)
-            cls.__DABSchema__[_fname] = _fvalue
-
-    def __call__(cls: Type, *args: Any, **kw: Any):  # intentionally untyped
-        """BaseElement new instance"""
-        obj = super().__call__(*args)
-
-        extensions: dict[str, Any] = {}
-
-        cls.populate_instance(  # pylint: disable=no-value-for-parameter
-            obj, extensions, *args, **kw
-        )
-        cls.freeze_instance_schema(  # pylint: disable=no-value-for-parameter
-            obj, extensions, *args, **kw
-        )
-        cls.apply_overrides(  # pylint: disable=no-value-for-parameter
-            obj, extensions, *args, **kw
-        )
-        cls.finalize_instance(obj, extensions)  # pylint: disable=no-value-for-parameter
-
-        return obj
-
-    def populate_instance(
-        cls: Type, obj: Any, extensions: dict[str, Any], *args: Any, **kw: Any
-    ):
-        """
-        Populate the new instance with field values from the class schema.
-
-        Copies each LAMField.value to an instance attribute (deep-frozen view).
-        """
-        for _fname, _fvalue in cls.__DABSchema__.items():
-            if isinstance(_fvalue, LAMField):
-                object.__setattr__(obj, _fname, _fvalue.value)
-
-    def freeze_instance_schema(
-        cls: Type, obj: Any, extensions: dict[str, Any], *args: Any, **kw: Any
-    ):
-        """
-        Freeze the instance's schema by wrapping DABFields into FrozenLAMField.
-
-        Creates a per-instance `__DABSchema__` dict where each field is read-only.
-        """
-        inst_schema = copy(obj.__DABSchema__)
-        for _fname, _fvalue in cls.__DABSchema__.items():
-            if isinstance(_fvalue, LAMField):
-                inst_schema[_fname] = FrozenLAMField(_fvalue)
-
-        if "features" in inst_schema:
-            inst_schema["features"] = dict(inst_schema["features"])
-
-        object.__setattr__(obj, "__DABSchema__", inst_schema)
-
-    def apply_overrides(cls, obj, extensions, *args, **kwargs):
-        """
-        Hook for runtime overrides at instance creation.
-
-        Invoked after the schema has been frozen but before finalize_instance.
-        Subclasses of _MetaElement can override this to support things like:
-
-          - Field overrides: MyApp(field=value)
-          - Feature overrides: MyApp(FeatureName=CustomFeature)
-          - Feature attachments: MyApp(NewFeature=FeatureClass)
-
-        By default this does nothing.
-        """
-
-    def finalize_instance(cls: Type, obj: Any, extensions: dict[str, Any]):
-        """
-        Finalization hook invoked at the end of instance construction.
-
-        Subclasses of the metaclass override this to attach runtime components
-        to the instance. (Example: BaseMetaAppliance instantiates bound Features
-        and sets them as attributes on the appliance instance.)
-        """
-
-    def install_instance_guard(cls: Type, extensions: dict[str, Any]):
-        """
-        Install the runtime `__setattr__` guard on the class.
-
-        After instances are constructed, prevents:
-          - creating new public fields,
-          - reassigning existing fields post-initialization.
-
-        Private/dunder attributes are exempt to allow internal bookkeeping.
-        """
-        orig_setattr = getattr(cls, "__setattr__")
-
-        # cls.orig_setattr = orig_setattr
-
-        def guarded_setattr(_self, key: str, value: Any):
-            if key.startswith("_"):  # allow private and dunder attrs
-                return orig_setattr(_self, key, value)
-            # block writes after init if key is readonly
-            if key in _self.__DABSchema__.keys():
-                if key in _self.__dict__:
-                    raise ReadOnlyField(f"{key} is read-only")
-            # elif key in _self.__DABSchema__["features"].keys():
-            #    if key in _self.__dict__:
-            #        raise ReadOnlyField(f"{key} is read-only")
-            else:
-                raise NewFieldForbidden("creating new fields is not allowed")
-
-            return orig_setattr(_self, key, value)
-
-        setattr(cls, "__setattr__", guarded_setattr)

src/dabmodel/meta/element.py

@@ -0,0 +1,844 @@
+from typing import Optional, TypeVar, get_origin, get_args, Any, Type, Union, Dict, Annotated
+
+from types import FunctionType, UnionType, new_class
+from copy import deepcopy, copy
+import sys
+import weakref
+import inspect, ast, textwrap
+
+
+from typeguard import check_type, TypeCheckError, CollectionCheckStrategy
+from frozendict import frozendict
+from ..tools import _resolve_annotation
+from ..lam_field.lam_field import LAMFieldFactory, LAMField, LAMField_Element
+from ..lam_field.lam_field_info import LAMFieldInfo
+
+from ..defines import ALLOWED_HELPERS_MATH, ALLOWED_HELPERS_DEFAULT, ALLOWED_MODEL_FIELDS_TYPES
+from ..base_element import BaseElement
+
+
+from ..exception import (
+    MultipleInheritanceForbidden,
+    BrokenInheritance,
+    ReadOnlyField,
+    NotAnnotatedField,
+    ReadOnlyFieldAnnotation,
+    InvalidFieldValue,
+    InvalidFieldAnnotation,
+    ImportForbidden,
+    FunctionForbidden,
+    NonExistingField,
+    InvalidInitializerType,
+    IncompletelyAnnotatedField,
+    UnsupportedFieldType,
+    WrongUsage,
+)
+
+# Cache per base class -> mutable variant
+_MUTABLE_VARIANTS = weakref.WeakKeyDictionary()
+
+
+def _merge_options(base_opts: tuple, *adds) -> tuple:
+    merged = list(base_opts)
+    for a in adds:
+        if a not in merged:
+            merged.append(a)
+    return tuple(merged)
+
+
+class IMutableVariant:
+    pass
+
+
+def get_mutable_variant(base: Type[BaseElement]) -> Type[BaseElement]:
+    """
+    Return a subclass of `base` that behaves the same except that instances
+    are created object-mutable (because the class was defined with options=(ObjectMutable,)).
+    """
+    print(f"____ Walking through: {base}")
+    print(f"bases: {base.__bases__}")
+
+    if base in (IElement, IFeature, IAppliance):
+        return base
+
+    if base.mutable_obj or issubclass(base, IMutableVariant):
+        print("already mutable")
+        return base  # already mutable
+
+    cached = _MUTABLE_VARIANTS.get(base)
+    if cached:
+        print("cached")
+        return cached
+
+    meta = type(base)  # keep the same metaclass
+    base_opts = getattr(base, "__lam_options__", ())
+    new_opts = _merge_options(base_opts, ObjectMutable, ClassMutable, _MutableClone)
+
+    # Recursively lift each direct base
+    lifted_bases = []
+    root_base: Optional[type[BaseElement]] = None
+    for b in base.__bases__:
+        if b in (IElement, IFeature, IAppliance):
+            if root_base:
+                raise BrokenInheritance(f"Multiple exclusive root bases (previous {root_base}, now {b}")
+            else:
+                root_base = b
+        elif b is BaseElement:
+            raise BrokenInheritance("BaseElement must not be used")
+        elif issubclass(b, IMutableVariant):
+            lifted_bases.append(b)
+        elif issubclass(b, BaseElement) and b is not BaseElement:
+            lifted_bases.append(get_mutable_variant(b))
+    print(f"lifted_bases: {lifted_bases}")
+
+    # Keep original behavior (inherit from C), AND attach lifted base variants
+    if len(lifted_bases) == 0:
+        if root_base is None:
+            raise BrokenInheritance("inheritance root not found")
+        bases = (root_base,)
+    else:
+        bases = tuple(lifted_bases) + (base,)  # ensures B' is subclass of B and A'
+
+    if IMutableVariant not in bases:
+        bases = bases + (IMutableVariant,)
+
+    name = f"{base.__name__}__Mutable"
+
+    def body(ns: dict[str, Any]) -> None:
+        ns["__module__"] = base.__module__
+        ns["__annotations__"] = base.__annotations__
+        # ns["__lam_class_mutable__"] = True
+        # ns["__lam_object_mutable__"] = True
+        ns["__qualname__"] = f"{base.__qualname__}__Mutable"
+        ns["__doc__"] = f"Mutable runtime variant of {base.__qualname__}"
+        for fname, fval in base.__lam_schema__.items():
+            if isinstance(fval, LAMField):
+                # v = getattr(base, fname)
+                ns[fname] = fval.clone_unfrozen().value
+
+    # IMPORTANT: pass options via kwds so your meta receives them
+    print(f"CREATING {name}")
+    variant = new_class(
+        name,
+        bases,
+        {"metaclass": meta, "options": new_opts},
+        body,
+    )
+    # Optional: register for pickling/import
+    sys.modules[base.__module__].__dict__[name] = variant
+
+    _MUTABLE_VARIANTS[base] = variant
+    return variant
+
+
+class IBaseElement(BaseElement):
+
+    def clone_as_mutable_variant(self, *, deep: bool = True, _memo: Dict[int, BaseElement] | None = None) -> BaseElement:
+
+        if isinstance(self, type):
+            raise WrongUsage("clone_as_mutable_variant can only be applied to an instance")
+
+        if self.mutable_obj:
+            return self  # already mutable
+
+        if _memo is None:
+            _memo = {}
+        sid = id(self)
+        if sid in _memo:
+            return _memo[sid]
+
+        dst_cls = get_mutable_variant(type(self))
+        # Create a fresh instance using the normal constructor path
+        dst = dst_cls()  # your meta will populate defaults; we'll overwrite below
+        _memo[sid] = dst
+
+        for fname, fval in self.__lam_schema__.items():
+            if isinstance(fval, LAMField):
+                v = getattr(self, fname)
+                if isinstance(v, BaseElement):
+                    if deep:
+                        v = v.clone_as_mutable_variant(deep=True, _memo=_memo)
+                    setattr(dst, fname, v)
+                else:
+                    setattr(dst, fname, fval.clone_unfrozen().value)
+
+                # dst.__dict__[fname] = v
+
+        return dst
+
+
+class IElement(IBaseElement): ...
+
+
+class IFeature(IBaseElement): ...
+
+
+class IAppliance(IBaseElement): ...
+
+
+def _check_annotation_definition(_type, first_layer: bool = True):  # pylint: disable=too-complex,too-many-return-statements
+    print(f"_type={_type}, {first_layer}")
+
+    _origin = get_origin(_type) or _type
+    _args = get_args(_type)
+
+    # handle Annotated[,]
+    if _origin is Annotated:
+        if not first_layer:
+            raise UnsupportedFieldType("Annotated[] is only supported as parent annotation")
+        return _check_annotation_definition(_args[0], False)
+
+    # handle Optional[] and Union[None,...]
+    if _origin is Union or _origin is UnionType:
+        if (len(_args) != 2) or (type(None) not in list(_args)) or (not first_layer):
+            raise UnsupportedFieldType(
+                "Union[] is only supported to implement Optional (takes 2 parameters) and is only supported as parent annotation"
+            )
+        return any(_check_annotation_definition(_, False) for _ in get_args(_type) if _ is not type(None))
+
+    # handle Dict[...]
+    if _origin is dict:
+        if len(_args) != 2:
+            raise IncompletelyAnnotatedField(f"Dict Annotation requires 2 inner definitions: {_type}")
+        if not _args[0] in ALLOWED_MODEL_FIELDS_TYPES:
+            raise IncompletelyAnnotatedField(f"Dict Key must be simple builtin: {_type}")
+        # return _check_annotation_definition(_args[1], False)
+        return any(_check_annotation_definition(_, False) for _ in _args)
+
+    # handle Tuple[]
+    if _origin is tuple:
+        if len(_args) == 0:
+            raise IncompletelyAnnotatedField(f"Annotation requires inner definition: {_type}")
+        if len(_args) == 2 and _args[1] is Ellipsis:
+            return _check_annotation_definition(_args[0], False)
+        return any(_check_annotation_definition(_, False) for _ in _args)
+
+    # handle Set[],Tuple[],FrozenSet[],List[]
+    if _origin in [set, frozenset, tuple, list]:
+        if len(_args) == 0:
+            raise IncompletelyAnnotatedField(f"Annotation requires inner definition: {_type}")
+        return any(_check_annotation_definition(_, False) for _ in _args)
+
+    if isinstance(_origin, type):
+        if issubclass(_origin, IElement):
+            return
+        elif issubclass(_origin, IAppliance):
+            raise UnsupportedFieldType(f"Nested Appliance are not supported: {_type}")
+
+    if _origin in ALLOWED_MODEL_FIELDS_TYPES:
+        return
+    raise UnsupportedFieldType(_origin)
+
+
+def _check_initializer_safety(func) -> None:
+    """
+    Preliminary structural check for __initializer__.
+
+    Policy (minimal):
+      - Forbid 'import' / 'from ... import ...' inside the initializer body.
+      - Forbid nested function definitions (closures/helpers) in the body.
+      - Allow lambdas.
+      - No restrictions on calls here (keep it simple).
+      - Optionally forbid closures (free vars) for determinism.
+    """
+    try:
+        src = inspect.getsource(func)
+    except OSError as exc:
+        # If source isn't available (rare), fail closed (or skip if you prefer)
+        raise FunctionForbidden("Cannot inspect __initializer__ source") from exc
+
+    src = textwrap.dedent(src)
+    mod = ast.parse(src)
+
+    # Find the FunctionDef node that corresponds to this initializer
+    init_node = next(
+        (n for n in mod.body if isinstance(n, (ast.FunctionDef, ast.AsyncFunctionDef)) and n.name == func.__name__),
+        None,
+    )
+    if init_node is None:
+        # Fallback: if not found, analyze nothing further to avoid false positives
+        return
+
+    for node in ast.walk(ast.Module(body=init_node.body, type_ignores=[])):
+        if isinstance(node, (ast.Import, ast.ImportFrom)):
+            raise ImportForbidden("imports disabled in __initializer")
+        if isinstance(node, (ast.FunctionDef, ast.AsyncFunctionDef)):
+            raise FunctionForbidden("Nested defs are forbidden in __initializer")
+        # if isinstance(node, ast.Lambda):
+        #    raise FunctionForbidden("Lambdas are forbidden in __initializer")
+
+    # Optional: forbid closures (keeps determinism; allows lambdas that don't capture)
+    if func.__code__.co_freevars:
+        # Inspect captured free vars
+        closure_vars = inspect.getclosurevars(func)
+        captured = {**closure_vars.globals, **closure_vars.nonlocals}
+        for name, val in captured.items():
+            if isinstance(val, type) and issubclass(val, IElement):
+                continue
+            if isinstance(val, (int, str, float, bool, type(None))):
+                continue
+            raise FunctionForbidden(f"Closures are forbidden in __initializer__ (captured: {name}={val!r})")
+
+
+def _blocked_import(*args, **kwargs):
+    raise ImportForbidden("imports disabled in __initializer")
+
+
+class ModelSpecView:
+    """ModelSpecView class
+    A class that will act as fake BaseElement proxy to allow setting values"""
+
+    __slots__ = ("_vals", "_types", "_touched", "_name", "_module")
+
+    def __init__(self, values: dict[str, Any], types_map: dict[str, type], name: str, module: str):
+        self._name: str
+        self._vals: dict[str, Any]
+        self._types: dict[str, type]
+        self._touched: set
+        self._module: str
+        object.__setattr__(self, "_vals", dict(values))
+        object.__setattr__(self, "_types", types_map)
+        object.__setattr__(self, "_name", name)
+        object.__setattr__(self, "_module", module)
+
+    @property
+    def __name__(self) -> str:
+        """returns proxified class' name"""
+        return self._name
+
+    @property
+    def __module__(self) -> str:
+        """returns proxified module's name"""
+        return self._module
+
+    @__module__.setter
+    def __module__(self, value: str):
+        pass
+
+    def __getattr__(self, name: str) -> Any:
+        """internal proxy getattr"""
+        if name not in self._types:
+            raise NonExistingField(f"Unknown field {name}")
+        return self._vals[name]
+
+    def __setattr__(self, name: str, value: Any):
+        """internal proxy setattr"""
+        if name not in self._types:
+            raise NonExistingField(f"Cannot set unknown field {name}")
+        T = self._types[name]
+
+        try:
+            check_type(
+                value,
+                T,
+                collection_check_strategy=CollectionCheckStrategy.ALL_ITEMS,
+            )
+        except TypeCheckError as exp:
+            raise InvalidFieldValue(f"Field <{name}> value is not of expected type {T}.") from exp
+
+        self._vals[name] = value
+
+    def export(self) -> dict:
+        """exports all proxified values"""
+        return dict(self._vals)
+
+
+T_Meta = TypeVar("T_Meta", bound="_MetaElement")
+T_BE = TypeVar("T_BE", bound="BaseElement")
+
+
+class ElementOptions:
+    pass
+
+
+class ClassMutable(ElementOptions):
+    pass
+
+
+class ObjectMutable(ElementOptions):
+    pass
+
+
+class _MutableClone(ElementOptions):
+    pass
+
+
+class _MetaElement(type):
+    """metaclass to use to build BaseElement"""
+
+    def __new__(
+        mcs: type["_MetaElement"],
+        name: str,
+        bases: tuple[type[BaseElement], ...],
+        namespace: dict[str, Any],
+        **kwargs,
+    ) -> Type:
+        """BaseElement new class"""
+
+        # create a dict to pass contextual arg onto the stack (multithread safe class init)
+        stack_exts: dict[str, Any] = {}
+        stack_exts["kwargs"] = kwargs
+
+        # retrieve options and normalize it (always a tuple)
+        if "options" not in stack_exts["kwargs"]:
+            stack_exts["kwargs"]["options"] = ()
+        elif not isinstance(stack_exts["kwargs"]["options"], tuple):
+            stack_exts["kwargs"]["options"] = (stack_exts["kwargs"]["options"],)
+        else:
+            stack_exts["kwargs"]["options"] = stack_exts["kwargs"]["options"]
+
+        # main class creation pipeline
+        mcs.check_class(name, bases, namespace, stack_exts)
+        mcs.process_class_fields(name, bases, namespace, stack_exts)
+        _cls = super().__new__(mcs, name, bases, namespace)
+        mcs.commit_fields(_cls, name, bases, namespace, stack_exts)
+        mcs.apply_initializer(_cls, name, bases, namespace, stack_exts)
+        mcs.finalize_class(_cls, name, bases, namespace, stack_exts)
+        if not _cls.__lam_class_mutable__:
+            _cls.freeze_class(True)
+        _cls.__lam_initialized__ = True
+
+        return _cls
+
+    @classmethod
+    def check_class(
+        mcs: type["_MetaElement"],
+        name: str,
+        bases: tuple[type[Any], ...],
+        namespace: dict[str, Any],  # pylint: disable=unused-argument
+        stack_exts: dict[str, Any],
+    ) -> None:
+        """
+        Early class-build hook.
+
+        Validates the inheritance shape, initializes an empty schema for root classes,
+        copies the parent schema for subclasses, and ensures all annotated fields
+        have a default (inserting `None` when missing).
+
+        This runs before the class object is created.
+        """
+
+        print(f"__NEW__ Defining {name}, bases {bases}")
+
+        if len(bases) > 1:
+            if _MutableClone not in stack_exts["kwargs"]["options"]:
+                raise MultipleInheritanceForbidden(f"Multiple inheritance is not supported by dabmodel: {bases}")
+
+        if len(bases) == 0:
+            raise BrokenInheritance(f"missing base class")
+
+        if not any([issubclass(base, BaseElement) for base in bases]):
+            raise BrokenInheritance(f"wrong base class: {bases}")
+
+        # handle schema/fields inheritance
+        mcs.inherit_schema(name, bases[0], namespace, stack_exts)
+
+        # force annotated fields without value to be still instantiated (with None)
+        if "__annotations__" in namespace:
+            for k_unknown in [_ for _ in namespace["__annotations__"] if _ not in namespace]:
+                namespace[k_unknown] = None
+
+        namespace["__lam_initialized__"] = False
+
+        # process options
+        namespace["__lam_class_mutable__"] = ClassMutable in stack_exts["kwargs"]["options"]
+        namespace["__lam_object_mutable__"] = ObjectMutable in stack_exts["kwargs"]["options"]
+        namespace["__lam_options__"] = stack_exts["kwargs"]["options"]
+
+    @classmethod
+    def inherit_schema(  # pylint: disable=too-complex,too-many-branches
+        mcs: type["_MetaElement"],
+        name: str,
+        base: type[Any],
+        namespace: dict[str, Any],
+        stack_exts: dict[str, Any],
+    ):
+        # create a new schema instance
+        namespace["__lam_schema__"] = {}
+        # copy elements from the parent class
+        namespace["__lam_schema__"].update(base.__lam_schema__)
+        # clone element (unfrozen)
+        for k, v in namespace["__lam_schema__"].items():
+            if isinstance(v, LAMField):
+                namespace["__lam_schema__"][k] = namespace["__lam_schema__"][k].clone_unfrozen()
+
+    @classmethod
+    def process_class_fields(  # pylint: disable=too-complex,too-many-branches
+        mcs: type["_MetaElement"],
+        name: str,
+        bases: tuple[type[Any], ...],
+        namespace: dict[str, Any],
+        stack_exts: dict[str, Any],
+    ):
+        """
+        Scan the class namespace and partition fields.
+
+        Detects:
+          - modified fields (shadowing parent values),
+          - new fields (present in annotations),
+          - the optional `__initializer` classmethod (in mangled or unmangled form).
+
+        Validates annotations and types and removes processed items from `namespace`
+        so they won't become normal attributes. Results are staged into:
+          stack_exts["new_fields"], stack_exts["modified_fields"], stack_exts["initializer"]
+        to be committed later.
+        """
+        # Fields Factory
+        stack_exts["modified_fields"] = {}
+        stack_exts["new_fields"] = {}
+        stack_exts["initializer"] = None
+        initializer_name: Optional[str] = None
+        for k, v in namespace.items():
+            print(f" {name} Processing Field: {k} / {v}")
+            # handling initializer method
+            if k == f"_{name}__initializer" or (name.startswith("_") and k == "__initializer"):
+                if not isinstance(v, classmethod):
+                    raise InvalidInitializerType("__initializer must be a classmethod")
+                stack_exts["initializer"] = v.__func__
+                if name.startswith("_"):
+                    initializer_name = "__initializer"
+                else:
+                    initializer_name = f"_{name}__initializer"
+            # skipping protected/private/dunder methods and attributes
+            elif k.startswith("_"):
+                pass
+            # skipping classmethods
+            elif isinstance(v, classmethod):
+                pass
+            # skipping methods
+            elif isinstance(v, FunctionType):
+                pass
+            # disallowing nested appliances
+            elif isinstance(v, IAppliance) or (isinstance(v, type) and issubclass(v, IAppliance)):
+                raise UnsupportedFieldType(f"Nested Appliance are not supported: {name}:{v}")
+            # supported Fields
+            else:
+                print(f"Staging Field: {k} / {v}")
+                # Modified fields (already in parent's schema as LAMField)
+                if k in namespace["__lam_schema__"] and isinstance(namespace["__lam_schema__"][k], LAMField):
+                    mcs.process_modified_field(name, bases, namespace, k, v, stack_exts)
+                # New fields (others)
+                else:
+                    mcs.process_new_field(name, bases, namespace, k, v, stack_exts)
+
+        # removing processed Fields and initializer from namespace (will add them back in the class later)
+        for k in stack_exts["new_fields"]:
+            del namespace[k]
+        for k in stack_exts["modified_fields"]:
+            del namespace[k]
+        if stack_exts["initializer"] is not None and initializer_name is not None:
+            del namespace[initializer_name]
+
+    @classmethod
+    def process_modified_field(
+        mcs: type["_MetaElement"],
+        name: str,
+        bases: tuple[type[Any], ...],
+        namespace: dict[str, Any],
+        _fname: str,
+        _fvalue: Any,
+        stack_exts: dict[str, Any],
+    ):  # pylint: disable=unused-argument
+        """
+        Handle a *modified* field declared by a subclass.
+
+        Forbids annotation changes, validates the new default value against
+        the inherited annotation, and stages the new default into `stack_exts["modified_fields"]`.
+        """
+        # forbid already existing Field's schema from being modified
+        if "__annotations__" in namespace and _fname in namespace["__annotations__"]:
+            raise ReadOnlyFieldAnnotation(f"annotations cannot be modified on derived classes {_fname}")
+        # validate the new value
+        namespace["__lam_schema__"][_fname].validate(_fvalue)
+        # stage the new value
+        stack_exts["modified_fields"][_fname] = _fvalue
+
+    @classmethod
+    def process_new_field(
+        mcs: type["_MetaElement"],
+        name: str,
+        bases: tuple[type[Any], ...],
+        namespace: dict[str, Any],
+        _fname: str,
+        _fvalue: Any,
+        stack_exts: dict[str, Any],
+    ):  # pylint: disable=unused-argument
+        """
+        Handle a *new* field declared on the class.
+
+        Resolves string annotations against a whitelist, validates `Annotated[...]`
+        payloads (allowing only LAMFieldInfo), checks the default value type,
+        and stages the field as a `LAMField` in `stack_exts["new_fields"]`.
+        """
+        print(f"New field: {_fname} / {_fvalue}")
+
+        # forbid non annotated field
+        if "__annotations__" not in namespace or _fname not in namespace["__annotations__"]:
+            raise NotAnnotatedField(f"Every dabmodel Fields must be annotated ({_fname})")
+
+        # check if annotations' format is correct and save them
+        if isinstance(namespace["__annotations__"][_fname], str):
+            namespace["__annotations__"][_fname] = _resolve_annotation(namespace["__annotations__"][_fname])
+
+        # effectively checking the value is conform to annotations
+        try:
+            _check_annotation_definition(namespace["__annotations__"][_fname])
+        except InvalidFieldAnnotation:
+            raise
+        except Exception as ex:
+            raise InvalidFieldAnnotation(f"Field <{_fname}> has not an allowed or valid annotation.") from ex
+
+        # extracting LAMFieldInfo from Annotated[] annotations
+        _finfo: LAMFieldInfo = LAMFieldInfo()
+        origin = get_origin(namespace["__annotations__"][_fname])
+        tname = getattr(origin, "__name__", "") or getattr(origin, "__qualname__", "") or str(origin)
+        if "Annotated" in tname:
+            args = get_args(namespace["__annotations__"][_fname])
+            if args:
+                if len(args) > 2:
+                    raise InvalidFieldAnnotation(f"Field <{_fname}> had invalid Annotated value.")
+                if len(args) == 2 and not issubclass(type(args[1]), LAMFieldInfo):
+                    raise InvalidFieldAnnotation("Only LAMFieldInfo object is allowed as Annotated data.")
+
+                _finfo = args[1]
+        # stage the new field
+        stack_exts["new_fields"][_fname] = LAMFieldFactory.create_field(_fname, _fvalue, namespace["__annotations__"][_fname], _finfo)
+
+    @classmethod
+    def commit_fields(
+        mcs: type["_MetaElement"],
+        cls,
+        name: str,
+        bases: tuple[type[Any], ...],
+        namespace: dict[str, Any],  # pylint: disable=unused-argument
+        stack_exts: dict[str, Any],
+    ):
+        """
+        Commit staged fields into the class schema (`__lam_schema__`).
+
+        - For modified fields: copy the parent's LAMField, update its value.
+        - For new fields: set the freshly built LAMField and record its source.
+        """
+
+        # updating values of modified fields
+        for k, v in stack_exts["modified_fields"].items():
+            cls.__lam_schema__[k].update_value(v)
+
+        # registering new fields
+        for k, v in stack_exts["new_fields"].items():
+            v.add_source(cls)
+            cls.__lam_schema__[k] = v
+
+    @classmethod
+    def prepare_initializer_fields(
+        mcs: type["_MetaElement"],
+        cls,
+        name: str,
+        bases: tuple[type[Any], ...],
+        namespace: dict[str, Any],  # pylint: disable=unused-argument
+        init_fieldvalues: dict[str, Any],
+        init_fieldtypes: dict[str, Any],
+        stack_exts: dict[str, Any],
+    ):
+        pass
+
+    @classmethod
+    def commit_initializer_fields(
+        mcs: type["_MetaElement"],
+        cls,
+        name: str,
+        bases: tuple[type[Any], ...],
+        namespace: dict[str, Any],  # pylint: disable=unused-argument
+        fakecls_exports: dict[str, Any],
+        stack_exts: dict[str, Any],
+    ):
+        pass
+
+    @classmethod
+    def apply_initializer(
+        mcs: type["_MetaElement"],
+        cls,
+        name: str,
+        bases: tuple[type[Any], ...],
+        namespace: dict[str, Any],  # pylint: disable=unused-argument
+        stack_exts: dict[str, Any],
+    ):
+        """
+        Apply the optional `__initializer` classmethod to compute derived defaults.
+
+        The initializer runs in a restricted, import-blocked environment using a
+        `ModelSpecView` proxy that enforces type checking on assignments.
+        On success, the computed values are validated and written back into the
+        class schema's DABFields.
+        """
+
+        if stack_exts["initializer"] is not None:
+            # checking initializer function sanity
+            _check_initializer_safety(stack_exts["initializer"])
+
+            # preparing initializer context values
+            init_fieldvalues = {}
+            init_fieldtypes = {}
+            for k, v in cls.__lam_schema__.items():
+                if isinstance(v, LAMField):
+                    # clone = v.clone_unfrozen().value
+                    clone = deepcopy(v.value)
+                    init_fieldvalues[k] = clone
+                    init_fieldtypes[k] = v.annotations
+            mcs.prepare_initializer_fields(cls, name, bases, namespace, init_fieldvalues, init_fieldtypes, stack_exts)
+            # creating a fake class container to hold the context
+            fakecls = ModelSpecView(init_fieldvalues, init_fieldtypes, cls.__name__, cls.__module__)
+            # fakecls = cls
+
+            # preparing a fake and safe environment
+            safe_globals = {
+                "__builtins__": {"__import__": _blocked_import},
+                **ALLOWED_HELPERS_DEFAULT,
+            }
+            # if stack_exts["initializer"].__code__.co_freevars:
+            #    raise FunctionForbidden("__initializer must not use closures")
+
+            # creating the fake call
+            safe_initializer = FunctionType(
+                stack_exts["initializer"].__code__,
+                safe_globals,
+                name=stack_exts["initializer"].__name__,
+                argdefs=stack_exts["initializer"].__defaults__,
+                closure=stack_exts["initializer"].__closure__,
+            )
+            # calling initializer
+            safe_initializer(fakecls)  # pylint: disable=not-callable
+
+            # copying values back to the class
+            fakecls_exports = fakecls.export()
+            for k, v in cls.__lam_schema__.items():
+                if isinstance(v, LAMField):
+                    cls.__lam_schema__[k].update_value(fakecls_exports[k])
+            mcs.commit_initializer_fields(cls, name, bases, namespace, fakecls_exports, stack_exts)
+
+    @classmethod
+    def finalize_class(
+        mcs: type["_MetaElement"],
+        cls,
+        name: str,
+        bases: tuple[type[Any], ...],
+        namespace: dict[str, Any],  # pylint: disable=unused-argument
+        stack_exts: dict[str, Any],
+    ):
+        # freezing the field schema
+        cls.__lam_schema__ = frozendict(cls.__lam_schema__)
+
+    def __setattr__(cls, name: str, value: Any):
+        if not hasattr(cls, "__lam_initialized__") or not getattr(cls, "__lam_initialized__"):
+            return super().__setattr__(name, value)
+
+        if name.startswith("_"):
+            return super().__setattr__(name, value)
+
+        if name not in cls.__lam_schema__:
+            raise NonExistingField(f"Can't create new class attributes: {name}")
+
+        if not cls.__lam_class_mutable__:
+            raise ReadOnlyField(f"Class is immutable.")
+
+        cls.__lam_schema__[name].update_value(value)
+        return
+
+    def __getattr__(cls, name) -> Any:
+        if hasattr(cls, "__lam_initialized__") and getattr(cls, "__lam_initialized__") and name in cls.__lam_schema__:
+            return cls.__lam_schema__[name].value
+        raise NonExistingField(f"Non existing class attribute: {name}")
+
+    def __call__(cls: Type, *args: Any, **kw: Any):  # intentionally untyped
+        """BaseElement new instance"""
+        cls.validate_schema_class()
+
+        obj = super().__call__(*args)
+
+        # create a dict to pass contextual arg onto the stack (multithread safe class init)
+        stack_exts: dict[str, Any] = {}
+
+        # create instance attributes from schema
+        cls.populate_instance(obj, stack_exts, *args, **kw)
+        cls.apply_overrides(obj, stack_exts, *args, **kw)
+        cls.finalize_instance(obj, stack_exts)
+
+        return obj
+
+    def populate_instance(cls: Type, obj: Any, stack_exts: dict[str, Any], *args: Any, **kw: Any):
+        """
+        Populate the new instance with field values from the class schema.
+
+        Copies each LAMField.value to an instance attribute (deep-frozen view).
+        """
+        obj.__lam_schema__ = dict(cls.__lam_schema__)
+        for k, v in obj.__lam_schema__.items():
+            if isinstance(v, LAMField):
+                unfrozen_clone = v.clone_unfrozen()
+                obj.__lam_schema__[k] = unfrozen_clone
+                if obj.__lam_object_mutable__:
+                    object.__setattr__(obj, k, unfrozen_clone.value)
+                else:
+                    object.__setattr__(obj, k, unfrozen_clone.frozen_value)
+
+    def apply_overrides(cls, obj, stack_exts, *args, **kwargs):
+        """
+        Hook for runtime overrides at instance creation.
+
+        Invoked after the schema has been frozen but before finalize_instance.
+        Subclasses of _MetaElement can override this to support things like:
+
+          - Field overrides: MyApp(field=value)
+        """
+
+        # --- field overrides (unchanged) ---
+        print("!!!???????")
+        for k, v in list(kwargs.items()):
+            if k in obj.__lam_schema__:  # regular field
+                print(f"??????? {k} {v}")
+                print(obj.__lam_schema__[k])
+
+                if isinstance(obj.__lam_schema__[k], LAMField_Element):
+                    valid_val = True
+                    try:
+                        obj.__lam_schema__[k].validate(v)
+                    except InvalidFieldValue:
+                        valid_val = False
+                    if valid_val:
+                        obj.__lam_schema__[k].update_value(v)
+                        if not obj.__lam_object_mutable__:
+                            object.__setattr__(obj, k, obj.__lam_schema__[k].frozen_value)
+                        else:
+                            object.__setattr__(obj, k, obj.__lam_schema__[k].value)
+                    elif isinstance(v, dict):
+                        raise RuntimeError("initializing Elem with dict is not supported yet")
+                    else:
+                        raise InvalidFieldValue(f"Element override for '{k}' must be a Feature subclass or dict, got {type(v)}")
+
+                else:
+                    obj.__lam_schema__[k].update_value(v)
+                    if not obj.__lam_object_mutable__:
+                        object.__setattr__(obj, k, obj.__lam_schema__[k].frozen_value)
+                    else:
+                        object.__setattr__(obj, k, obj.__lam_schema__[k].value)
+                kwargs.pop(k)
+
+        if kwargs:
+            unknown = ", ".join(sorted(kwargs))
+            raise InvalidFieldValue(f"Unknown parameters: {unknown}")
+
+    def finalize_instance(cls: Type, obj: Any, stack_exts: dict[str, Any]):
+        """
+        Finalization hook invoked at the end of instance construction.
+
+        Subclasses of the metaclass override this to attach runtime components
+        to the instance. (Example: BaseMetaAppliance instantiates bound Features
+        and sets them as attributes on the appliance instance.)
+        """
+        obj.__lam_schema__ = frozendict(obj.__lam_schema__)
+
+        if not obj.__lam_object_mutable__:
+            for v in obj.__lam_schema__.values():
+                if isinstance(v, LAMField):
+                    v.freeze()
+            obj.freeze(True)

src/dabmodel/meta/feature.py

@@ -1,6 +1,5 @@
 from typing import Type, Any
-from .base import _MetaElement
-from ..exception import FeatureNotBound
+from .element import _MetaElement
 
 
 class _MetaFeature(_MetaElement):
@@ -8,12 +7,18 @@ class _MetaFeature(_MetaElement):
     Feature specific metaclass code
     """
 
-    def __call__(cls: Type, *args: Any, **kw: Any):  # intentionally untyped
-        """BaseFeature new instance"""
+    @classmethod
+    def finalize_class(
+        mcs: type["_MetaElement"],
+        cls,
+        name: str,
+        bases: tuple[type[Any], ...],
+        namespace: dict[str, Any],  # pylint: disable=unused-argument
+        stack_exts: dict[str, Any],
+    ):
+        if "appliance" in stack_exts["kwargs"]:
+            cls.bind_appliance(stack_exts["kwargs"]["appliance"])
 
-        if cls._BoundAppliance is None:
-            raise FeatureNotBound()
-
-        obj = super().__call__(*args, **kw)
-
-        return obj
+    def finalize_instance(cls: Type, obj: Any, stack_exts: dict[str, Any]):
+        cls.check_appliance_bound()
+        super().finalize_instance(obj, stack_exts)

src/dabmodel/tools.py

@@ -1,10 +1,36 @@
 """library's internal tools"""
 
+from collections import ChainMap
+from typing import (
+    Any,
+    Annotated,
+    get_origin,
+    get_args,
+    Union,
+    Self,
+    Optional,
+    List,
+    Dict,
+    Tuple,
+    Set,
+    FrozenSet,
+    Mapping,
+    Callable,
+)
+import typing
+from dataclasses import dataclass
+from types import UnionType, NoneType
+import types
 from uuid import UUID
 from datetime import datetime
 import json
+import inspect
 
-from frozendict import deepfreeze
+
+from frozendict import deepfreeze, frozendict
+
+from .defines import ALLOWED_ANNOTATIONS, ALLOWED_MODEL_FIELDS_TYPES
+from .exception import IncompletelyAnnotatedField, UnsupportedFieldType
 
 
 class LAMJSONEncoder(json.JSONEncoder):
@@ -30,3 +56,20 @@ def LAMdeepfreeze(value):
     if isinstance(value, tuple):
         return tuple(LAMdeepfreeze(v) for v in value)
     return value
+
+
+def is_data_attribute(name: str, value: any) -> bool:
+    if name.startswith("_"):
+        return False
+    if isinstance(value, (staticmethod, classmethod, property)):
+        return False
+    if inspect.isfunction(value) or inspect.ismethoddescriptor(value):
+        return False
+    return True
+
+
+def _resolve_annotation(ann):
+    if isinstance(ann, str):
+        # Safe eval against a **whitelist** only
+        return eval(ann, {"__builtins__": {}}, ALLOWED_ANNOTATIONS)  # pylint: disable=eval-used
+    return ann

test/test_AnnotationTool.py

@@ -0,0 +1,53 @@
+# dabmodel (c) by chacha
+#
+# dabmodel  is licensed under a
+# Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International Unported License.
+#
+# You should have received a copy of the license along with this
+# work.  If not, see <https://creativecommons.org/licenses/by-nc-sa/4.0/>.
+
+import unittest
+from typing import Annotated, Union, Optional
+import sys
+import subprocess
+from os import chdir, environ
+from pathlib import Path
+
+print(__name__)
+print(__package__)
+
+from src import dabmodel as dm
+
+testdir_path = Path(__file__).parent.resolve()
+chdir(testdir_path.parent.resolve())
+
+
+class AnnotationsWalkerTest(unittest.TestCase):
+    def setUp(self):
+        print("\n->", unittest.TestCase.id(self))
+
+    def test_validate(self):
+        ann = dict[int, list[int]] | dict[int, list[int | str]]
+        val = {1: [2], 2: ["a", [1]]}
+
+        res = dm.tools.AnnotationWalker(ann, (dm.tools.HorizontalValidationTrigger(val),))
+        res.run()
+
+    def test_simple(self):
+        print(isinstance(None, type(None)))
+        print("\n== From OBJs ==")
+        res = dm.tools.AnnotationWalker(Annotated[Optional[dict[int, list[str]]], "comment"], (dm.tools.LAMSchemaValidation(),))
+        print(f"res={res.run()}")
+
+        print("\n== From STRING ==")
+        res = dm.tools.AnnotationWalker('Annotated[Optional[dict[int, list[str]]], "comment"]', (dm.tools.LAMSchemaValidation(),))
+        print(f"res={res.run()}")
+
+        res = dm.tools.AnnotationWalker(Annotated[Optional[dict[int, list[None]]], "comment"], (dm.tools.LAMSchemaValidation(),))
+        print(f"res={res.run()}")
+
+
+# ---------- main ----------
+
+if __name__ == "__main__":
+    unittest.main()

test/test_element.py

@@ -0,0 +1,862 @@
+# dabmodel (c) by chacha
+#
+# dabmodel  is licensed under a
+# Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International Unported License.
+#
+# You should have received a copy of the license along with this
+# work.  If not, see <https://creativecommons.org/licenses/by-nc-sa/4.0/>.
+
+import unittest
+from typing import Annotated, Union
+import sys
+import subprocess
+from os import chdir, environ
+from pathlib import Path
+
+print(__name__)
+print(__package__)
+
+from src import dabmodel as dm
+
+testdir_path = Path(__file__).parent.resolve()
+chdir(testdir_path.parent.resolve())
+
+
+class ElementTest(unittest.TestCase):
+    def setUp(self):
+        print("\n->", unittest.TestCase.id(self))
+
+    def test_element_simple(self):
+        class E(dm.Element):
+            ivalue: int = 43
+            strvalue: str = "test"
+            fvalue: float = 1.4322
+            ar_int: list[int] = [1, 54, 65]
+            ar_int2: list[int] = [1, 54, 65]
+
+        class A(dm.Appliance):
+            elem: E = E(ivalue=45, strvalue="coucou", ar_int=[5, 7])
+
+        a = A()
+
+        self.assertIsInstance(a.elem, E)
+        self.assertIsInstance(a.elem.ivalue, int)
+        self.assertEqual(a.elem.ivalue, 45)
+        self.assertIsInstance(a.elem.strvalue, str)
+        self.assertEqual(a.elem.strvalue, "coucou")
+        self.assertIsInstance(a.elem.fvalue, float)
+        self.assertEqual(a.elem.fvalue, 1.4322)
+        self.assertIsInstance(a.elem.ar_int, tuple)
+        self.assertEqual(a.elem.ar_int, (5, 7))
+        self.assertIsInstance(a.elem.ar_int2, tuple)
+        self.assertEqual(a.elem.ar_int2, (1, 54, 65))
+
+    def test_element_in_container(self):
+        class E(dm.Element):
+            ivalue: int = 43
+            strvalue: str = "test"
+            fvalue: float = 1.4322
+            ar_int: list[int] = [1, 54, 65]
+            ar_int2: list[int] = [1, 54, 65]
+
+        class A(dm.Appliance):
+            elems: list[E] = [
+                E(ivalue=45, strvalue="coucou", ar_int=[5, 7]),
+                E(ivalue=46, strvalue="coucou2", ar_int=[50, 7]),
+            ]
+
+        a = A()
+
+        self.assertIsInstance(a.elems, tuple)
+        self.assertEqual(len(a.elems), 2)
+
+        self.assertIsInstance(a.elems[0], E)
+        self.assertIsInstance(a.elems[0].ivalue, int)
+        self.assertEqual(a.elems[0].ivalue, 45)
+        self.assertIsInstance(a.elems[0].strvalue, str)
+        self.assertEqual(a.elems[0].strvalue, "coucou")
+        self.assertIsInstance(a.elems[0].fvalue, float)
+        self.assertEqual(a.elems[0].fvalue, 1.4322)
+        self.assertIsInstance(a.elems[0].ar_int, tuple)
+        self.assertEqual(a.elems[0].ar_int, (5, 7))
+        self.assertIsInstance(a.elems[0].ar_int2, tuple)
+        self.assertEqual(a.elems[0].ar_int2, (1, 54, 65))
+
+        self.assertIsInstance(a.elems[1], E)
+        self.assertIsInstance(a.elems[1].ivalue, int)
+        self.assertEqual(a.elems[1].ivalue, 46)
+        self.assertIsInstance(a.elems[1].strvalue, str)
+        self.assertEqual(a.elems[1].strvalue, "coucou2")
+        self.assertIsInstance(a.elems[1].fvalue, float)
+        self.assertEqual(a.elems[1].fvalue, 1.4322)
+        self.assertIsInstance(a.elems[1].ar_int, tuple)
+        self.assertEqual(a.elems[1].ar_int, (50, 7))
+        self.assertIsInstance(a.elems[1].ar_int2, tuple)
+        self.assertEqual(a.elems[1].ar_int2, (1, 54, 65))
+
+    def test_class_frozen(self):
+        class E(dm.Element):
+            ivalue: int = 43
+            strvalue: str = "test"
+            fvalue: float = 1.4322
+            ar_int: list[int] = [1, 54, 65]
+
+        with self.assertRaises(dm.ReadOnlyField):
+            E.ivalue = 3
+
+        with self.assertRaises(dm.ReadOnlyField):
+            E.strvalue = "toto"
+
+        with self.assertRaises(dm.ReadOnlyField):
+            E.fvalue = 3.14
+
+        with self.assertRaises(AttributeError):
+            E.ar_int.append(5)
+
+    def test_instance_frozen(self):
+        class E(dm.Element):
+            ivalue: int = 43
+            strvalue: str = "test"
+            fvalue: float = 1.4322
+            ar_int: list[int] = [1, 54, 65]
+
+        e = E()
+
+        with self.assertRaises(dm.ReadOnlyField):
+            e.ivalue = 3
+
+        with self.assertRaises(dm.ReadOnlyField):
+            e.strvalue = "toto"
+
+        with self.assertRaises(dm.ReadOnlyField):
+            e.fvalue = 3.14
+
+        with self.assertRaises(AttributeError):
+            e.ar_int.append(5)
+
+    def test_composition_frozen(self):
+        class E(dm.Element):
+            ivalue: int = 43
+            strvalue: str = "test"
+            fvalue: float = 1.4322
+            ar_int: list[int] = [1, 54, 65]
+            ar_int2: list[int] = [1, 54, 65]
+
+        class A(dm.Appliance):
+            elems: list[E] = [
+                E(ivalue=45, strvalue="coucou", ar_int=[5, 7]),
+                E(ivalue=46, strvalue="coucou2", ar_int=[50, 7]),
+            ]
+            elem: E = E()
+
+        a = A()
+
+        with self.assertRaises(AttributeError):
+            a.elems.add(E())
+
+        with self.assertRaises(dm.ReadOnlyField):
+            a.elem.ivalue = 1
+
+        with self.assertRaises(dm.ReadOnlyField):
+            a.elems[0].ivalue = 1
+
+    def test_element_inheritance(self):
+        class E(dm.Element):
+            ivalue: int = 43
+            strvalue: str = "test"
+            fvalue: float = 1.4322
+            ar_int: list[int] = [1, 54, 65]
+            ar_int2: list[int] = [1, 54, 65]
+
+        class E2(E):
+            ivalue2: int = 43
+
+        class A(dm.Appliance):
+            elems: list[E] = [
+                E(ivalue=45, strvalue="coucou", ar_int=[5, 7]),
+                E2(ivalue=46, strvalue="coucou2", ar_int=[50, 7], ivalue2=32),
+            ]
+            elem: E = E()
+            elem2: E2 = E2(ivalue=7, ivalue2=33)
+
+        a = A()
+
+        self.assertIsInstance(a.elems, tuple)
+        self.assertEqual(len(a.elems), 2)
+
+        self.assertIsInstance(a.elems[0], E)
+        self.assertIsInstance(a.elems[0].ivalue, int)
+        self.assertEqual(a.elems[0].ivalue, 45)
+        self.assertIsInstance(a.elems[0].strvalue, str)
+        self.assertEqual(a.elems[0].strvalue, "coucou")
+        self.assertIsInstance(a.elems[0].fvalue, float)
+        self.assertEqual(a.elems[0].fvalue, 1.4322)
+        self.assertIsInstance(a.elems[0].ar_int, tuple)
+        self.assertEqual(a.elems[0].ar_int, (5, 7))
+        self.assertIsInstance(a.elems[0].ar_int2, tuple)
+        self.assertEqual(a.elems[0].ar_int2, (1, 54, 65))
+
+        self.assertIsInstance(a.elems[1], E2)
+        self.assertIsInstance(a.elems[1].ivalue, int)
+        self.assertEqual(a.elems[1].ivalue, 46)
+        self.assertIsInstance(a.elems[1].ivalue2, int)
+        self.assertEqual(a.elems[1].ivalue2, 32)
+        self.assertIsInstance(a.elems[1].strvalue, str)
+        self.assertEqual(a.elems[1].strvalue, "coucou2")
+        self.assertIsInstance(a.elems[1].fvalue, float)
+        self.assertEqual(a.elems[1].fvalue, 1.4322)
+        self.assertIsInstance(a.elems[1].ar_int, tuple)
+        self.assertEqual(a.elems[1].ar_int, (50, 7))
+        self.assertIsInstance(a.elems[1].ar_int2, tuple)
+        self.assertEqual(a.elems[1].ar_int2, (1, 54, 65))
+
+        self.assertIsInstance(a.elem, E)
+        self.assertIsInstance(a.elem.ivalue, int)
+        self.assertEqual(a.elem.ivalue, 43)
+        self.assertIsInstance(a.elem.strvalue, str)
+        self.assertEqual(a.elem.strvalue, "test")
+        self.assertIsInstance(a.elem.fvalue, float)
+        self.assertEqual(a.elem.fvalue, 1.4322)
+        self.assertIsInstance(a.elem.ar_int, tuple)
+        self.assertEqual(a.elem.ar_int, (1, 54, 65))
+        self.assertIsInstance(a.elem.ar_int2, tuple)
+        self.assertEqual(a.elem.ar_int2, (1, 54, 65))
+
+        self.assertIsInstance(a.elem2, E2)
+        self.assertIsInstance(a.elem2.ivalue, int)
+        self.assertEqual(a.elem2.ivalue, 7)
+        self.assertIsInstance(a.elem2.ivalue2, int)
+        self.assertEqual(a.elem2.ivalue2, 33)
+        self.assertIsInstance(a.elem2.strvalue, str)
+        self.assertEqual(a.elem2.strvalue, "test")
+        self.assertIsInstance(a.elem2.fvalue, float)
+        self.assertEqual(a.elem2.fvalue, 1.4322)
+        self.assertIsInstance(a.elem2.ar_int, tuple)
+        self.assertEqual(a.elem2.ar_int, (1, 54, 65))
+        self.assertIsInstance(a.elem2.ar_int2, tuple)
+        self.assertEqual(a.elem2.ar_int2, (1, 54, 65))
+
+    def test_element_initializer(self):
+        class E(dm.Element):
+            ivalue: int = 43
+            strvalue: str = "test"
+            fvalue: float = 1.4322
+            ar_int: list[int] = [1, 54, 65]
+            ar_int2: list[int] = [1, 54, 65]
+
+        class A(dm.Appliance):
+            elem: E = E(ivalue=45, strvalue="coucou", ar_int=[5, 7])
+
+            @classmethod
+            def __initializer(self):
+                self.elem = E(ivalue=12, strvalue="coucou", ar_int=[5, 7])
+
+        a = A()
+
+        self.assertIsInstance(a.elem, E)
+        self.assertIsInstance(a.elem.ivalue, int)
+        self.assertEqual(a.elem.ivalue, 12)
+        self.assertIsInstance(a.elem.strvalue, str)
+        self.assertEqual(a.elem.strvalue, "coucou")
+        self.assertIsInstance(a.elem.fvalue, float)
+        self.assertEqual(a.elem.fvalue, 1.4322)
+        self.assertIsInstance(a.elem.ar_int, tuple)
+        self.assertEqual(a.elem.ar_int, (5, 7))
+        self.assertIsInstance(a.elem.ar_int2, tuple)
+        self.assertEqual(a.elem.ar_int2, (1, 54, 65))
+
+    def test_element_in_container_initializer(self):
+        class E(dm.Element):
+            ivalue: int = 43
+            strvalue: str = "test"
+            fvalue: float = 1.4322
+            ar_int: list[int] = [1, 54, 65]
+            ar_int2: list[int] = [1, 54, 65]
+
+        class A(dm.Appliance):
+            elems: list[E] = [E(ivalue=45, strvalue="coucou", ar_int=[5, 7])]
+
+        class B(A):
+            @classmethod
+            def __initializer(cls):
+                cls.elems.append(E(ivalue=46, strvalue="coucou2", ar_int=[50, 7]))
+
+        a = A()
+        b = B()
+
+        self.assertIsInstance(a.elems, tuple)
+        self.assertEqual(len(a.elems), 1)
+
+        self.assertIsInstance(a.elems[0], E)
+        self.assertIsInstance(a.elems[0].ivalue, int)
+        self.assertEqual(a.elems[0].ivalue, 45)
+        self.assertIsInstance(a.elems[0].strvalue, str)
+        self.assertEqual(a.elems[0].strvalue, "coucou")
+        self.assertIsInstance(a.elems[0].fvalue, float)
+        self.assertEqual(a.elems[0].fvalue, 1.4322)
+        self.assertIsInstance(a.elems[0].ar_int, tuple)
+        self.assertEqual(a.elems[0].ar_int, (5, 7))
+        self.assertIsInstance(a.elems[0].ar_int2, tuple)
+        self.assertEqual(a.elems[0].ar_int2, (1, 54, 65))
+
+        self.assertIsInstance(b.elems, tuple)
+        self.assertEqual(len(b.elems), 2)
+
+        self.assertIsInstance(b.elems[0], E)
+        self.assertIsInstance(b.elems[0].ivalue, int)
+        self.assertEqual(b.elems[0].ivalue, 45)
+        self.assertIsInstance(b.elems[0].strvalue, str)
+        self.assertEqual(b.elems[0].strvalue, "coucou")
+        self.assertIsInstance(b.elems[0].fvalue, float)
+        self.assertEqual(b.elems[0].fvalue, 1.4322)
+        self.assertIsInstance(b.elems[0].ar_int, tuple)
+        self.assertEqual(b.elems[0].ar_int, (5, 7))
+        self.assertIsInstance(b.elems[0].ar_int2, tuple)
+        self.assertEqual(b.elems[0].ar_int2, (1, 54, 65))
+
+        self.assertIsInstance(b.elems[1], E)
+        self.assertIsInstance(b.elems[1].ivalue, int)
+        self.assertEqual(b.elems[1].ivalue, 46)
+        self.assertIsInstance(b.elems[1].strvalue, str)
+        self.assertEqual(b.elems[1].strvalue, "coucou2")
+        self.assertIsInstance(b.elems[1].fvalue, float)
+        self.assertEqual(b.elems[1].fvalue, 1.4322)
+        self.assertIsInstance(b.elems[1].ar_int, tuple)
+        self.assertEqual(b.elems[1].ar_int, (50, 7))
+        self.assertIsInstance(b.elems[1].ar_int2, tuple)
+        self.assertEqual(b.elems[1].ar_int2, (1, 54, 65))
+
+    def test_method(self):
+        class E(dm.Element):
+            ivalue: int = 43
+
+            def get_increment(self) -> int:
+                return self.ivalue + 1
+
+            def increment(self) -> int:
+                return type(self)(ivalue=self.ivalue + 1)
+
+        class A(dm.Appliance):
+            elem: E = E(ivalue=45)
+
+        a = A()
+        self.assertIsInstance(a.elem, E)
+        self.assertEqual(a.elem.ivalue, 45)
+        self.assertEqual(a.elem.get_increment(), 46)
+
+        class B(A):
+
+            @classmethod
+            def __initializer(cls):
+                cls.elem = cls.elem.increment()
+
+        b = B()
+        self.assertEqual(b.elem.ivalue, 46)
+        self.assertEqual(b.elem.get_increment(), 47)
+
+    def test_initializer_appliance_function_forbidden(self):
+        def test_fun() -> int:
+            return 12
+
+        class E(dm.Element):
+            ivalue: int = 43
+
+        with self.assertRaises(dm.FunctionForbidden):
+
+            class B(dm.Element):
+                elem: E = E()
+
+                @classmethod
+                def __initializer(cls):
+                    cls.elem.ivalue = test_fun()
+
+        with self.assertRaises(dm.FunctionForbidden):
+
+            class C(dm.Element):
+                elem: E = E()
+
+                @classmethod
+                def __initializer(cls):
+                    cls.elem = E(ivalue=test_fun())
+
+    def test_mutable_class2_newelement_fails(self):
+
+        class E(dm.Element, options=(dm.ClassMutable)):
+            ivalue: int = 43
+
+        with self.assertRaises(dm.NonExistingField):
+            E.test = 123
+        e = E()
+        with self.assertRaises(dm.NonExistingField):
+            e.test = 123
+
+    def test_mutable_class_freeze(self):
+
+        class E(dm.Element, options=(dm.ClassMutable)):
+            ivalue: int = 43
+
+        E.ivalue = 12
+        self.assertEqual(E.ivalue, 12)
+        E.freeze_class()
+        self.assertEqual(E.ivalue, 12)
+        with self.assertRaises(dm.ReadOnlyField):
+            E.ivalue = 13
+        self.assertEqual(E.ivalue, 12)
+        e = E()
+        self.assertEqual(e.ivalue, 12)
+        with self.assertRaises(dm.ReadOnlyField):
+            e.ivalue = 14
+        self.assertEqual(e.ivalue, 12)
+
+    def test_mutable_object_freeze(self):
+
+        class E(dm.Element, options=(dm.ObjectMutable)):
+            ivalue: int = 43
+
+        self.assertEqual(E.ivalue, 43)
+        with self.assertRaises(dm.ReadOnlyField):
+            E.ivalue = 13
+        self.assertEqual(E.ivalue, 43)
+        e = E()
+        self.assertEqual(e.ivalue, 43)
+        e.ivalue = 14
+        self.assertEqual(e.ivalue, 14)
+        e.freeze()
+        self.assertEqual(e.ivalue, 14)
+        with self.assertRaises(dm.ReadOnlyField):
+            e.ivalue = 15
+        self.assertEqual(e.ivalue, 14)
+
+    def test_mutable_object_and_class_freeze(self):
+
+        class E(dm.Element, options=(dm.ObjectMutable, dm.ClassMutable)):
+            ivalue: int = 43
+
+        self.assertEqual(E.ivalue, 43)
+        E.ivalue = 13
+        self.assertEqual(E.ivalue, 13)
+        e = E()
+        self.assertEqual(e.ivalue, 13)
+        e.ivalue = 14
+        self.assertEqual(e.ivalue, 14)
+        e.freeze()
+        self.assertEqual(e.ivalue, 14)
+        with self.assertRaises(dm.ReadOnlyField):
+            e.ivalue = 15
+        self.assertEqual(e.ivalue, 14)
+
+    def test_mutable_object_and_class_freeze_2(self):
+
+        class E(dm.Element, options=(dm.ObjectMutable, dm.ClassMutable)):
+            ivalue: int = 43
+
+        self.assertFalse(E.__lam_schema__["ivalue"].is_frozen())
+        E.freeze_class()
+        self.assertTrue(E.__lam_schema__["ivalue"].is_frozen())
+        e = E()
+        self.assertFalse(e.__lam_schema__["ivalue"].is_frozen())
+        e.freeze()
+        self.assertTrue(e.__lam_schema__["ivalue"].is_frozen())
+
+    def test_mutable_class_freeze_container(self):
+
+        class E(dm.Element, options=(dm.ClassMutable)):
+            ar_ivalue: list[int] = [43]
+
+        E.ar_ivalue.append(12)
+        self.assertEqual(E.ar_ivalue, [43, 12])
+        E.freeze_class()
+        self.assertEqual(E.ar_ivalue, (43, 12))
+        with self.assertRaises(AttributeError):
+            E.ar_ivalue.append(52)
+        self.assertEqual(E.ar_ivalue, (43, 12))
+        e = E()
+        self.assertEqual(e.ar_ivalue, (43, 12))
+        with self.assertRaises(AttributeError):
+            e.ar_ivalue.append(52)
+        self.assertEqual(e.ar_ivalue, (43, 12))
+
+    def test_mutable_object_freeze_container(self):
+
+        class E(dm.Element, options=(dm.ObjectMutable)):
+            ar_ivalue: list[int] = [43, 54]
+
+        self.assertEqual(E.ar_ivalue, (43, 54))
+        with self.assertRaises(AttributeError):
+            E.ar_ivalue.append(13)
+        self.assertEqual(E.ar_ivalue, (43, 54))
+        e = E()
+        self.assertEqual(e.ar_ivalue, [43, 54])
+        e.ar_ivalue.append(32)
+        self.assertEqual(e.ar_ivalue, [43, 54, 32])
+        e.freeze()
+        self.assertEqual(e.ar_ivalue, (43, 54, 32))
+        with self.assertRaises(AttributeError):
+            e.ar_ivalue.append(12)
+        self.assertEqual(e.ar_ivalue, (43, 54, 32))
+
+    def test_mutable_object_and_class_freeze_container(self):
+
+        class E(dm.Element, options=(dm.ObjectMutable, dm.ClassMutable)):
+            ar_ivalue: list[int] = [43, 54]
+
+        self.assertEqual(E.ar_ivalue, [43, 54])
+        E.ar_ivalue.append(13)
+        self.assertEqual(E.ar_ivalue, [43, 54, 13])
+        e = E()
+        self.assertEqual(e.ar_ivalue, [43, 54, 13])
+        e.ar_ivalue.append(14)
+        self.assertEqual(e.ar_ivalue, [43, 54, 13, 14])
+        e.freeze()
+        self.assertEqual(e.ar_ivalue, (43, 54, 13, 14))
+        with self.assertRaises(AttributeError):
+            e.ar_ivalue.append(15)
+        self.assertEqual(e.ar_ivalue, (43, 54, 13, 14))
+
+    def test_mutable_class_freeze_inheritance(self):
+
+        class E(dm.Element, options=(dm.ClassMutable)):
+            ivalue: int = 12
+
+        class E2(E):
+            pass
+
+        self.assertEqual(E2.ivalue, 12)
+        with self.assertRaises(dm.ReadOnlyField):
+            E2.ivalue = 13
+        self.assertEqual(E2.ivalue, 12)
+        e = E2()
+        self.assertEqual(e.ivalue, 12)
+        with self.assertRaises(dm.ReadOnlyField):
+            e.ivalue = 14
+        self.assertEqual(e.ivalue, 12)
+
+    def test_mutable_object_freeze_inheritance(self):
+
+        class E(dm.Element, options=(dm.ObjectMutable)):
+            ivalue: int = 12
+
+        class E2(E):
+            pass
+
+        self.assertEqual(E2.ivalue, 12)
+        with self.assertRaises(dm.ReadOnlyField):
+            E2.ivalue = 13
+        self.assertEqual(E2.ivalue, 12)
+        e = E2()
+        self.assertEqual(e.ivalue, 12)
+        with self.assertRaises(dm.ReadOnlyField):
+            e.ivalue = 14
+        self.assertEqual(e.ivalue, 12)
+
+    def test_mutable_object_and_class_freeze_inheritance(self):
+
+        class E(dm.Element, options=(dm.ObjectMutable, dm.ClassMutable)):
+            ivalue: int = 12
+
+        class E2(E):
+            pass
+
+        self.assertEqual(E2.ivalue, 12)
+        with self.assertRaises(dm.ReadOnlyField):
+            E2.ivalue = 13
+        self.assertEqual(E2.ivalue, 12)
+        e = E2()
+        self.assertEqual(e.ivalue, 12)
+        with self.assertRaises(dm.ReadOnlyField):
+            e.ivalue = 14
+        self.assertEqual(e.ivalue, 12)
+
+    def test_mutable_object_and_class_freeze_inheritance_noleak(self):
+
+        class E(dm.Element, options=(dm.ObjectMutable, dm.ClassMutable)):
+            ivalue: int = 12
+
+        class E2(E):
+            pass
+
+        self.assertEqual(E2.ivalue, 12)
+        with self.assertRaises(dm.ReadOnlyField):
+            E2.ivalue = 13
+        self.assertEqual(E2.ivalue, 12)
+        e2 = E2()
+        self.assertEqual(e2.ivalue, 12)
+        with self.assertRaises(dm.ReadOnlyField):
+            e2.ivalue = 14
+        self.assertEqual(e2.ivalue, 12)
+
+        # no Leak
+
+        self.assertEqual(E.ivalue, 12)
+        E.ivalue = 13
+        self.assertEqual(E.ivalue, 13)
+        e = E()
+        self.assertEqual(e.ivalue, 13)
+        e.ivalue = 14
+        self.assertEqual(e.ivalue, 14)
+        e.freeze()
+        self.assertEqual(e.ivalue, 14)
+        with self.assertRaises(dm.ReadOnlyField):
+            e.ivalue = 15
+        self.assertEqual(e.ivalue, 14)
+
+        # no Leak 2
+
+        self.assertEqual(E2.ivalue, 12)
+        with self.assertRaises(dm.ReadOnlyField):
+            E2.ivalue = 13
+        self.assertEqual(E2.ivalue, 12)
+        e2 = E2()
+        self.assertEqual(e2.ivalue, 12)
+        with self.assertRaises(dm.ReadOnlyField):
+            e2.ivalue = 14
+        self.assertEqual(e2.ivalue, 12)
+
+    def test_mutable_class_freeze_nested_element(self):
+
+        class NElem(dm.Element):
+            ivalue: int = 43
+
+        class E(dm.Element, options=(dm.ClassMutable)):
+            e: NElem = NElem()
+
+        E.e.ivalue = 12
+        self.assertEqual(E.e.ivalue, 12)
+        E.freeze_class()
+        self.assertEqual(E.e.ivalue, 12)
+        with self.assertRaises(dm.ReadOnlyField):
+            E.e.ivalue = 13
+        self.assertEqual(E.e.ivalue, 12)
+        e = E()
+        self.assertEqual(e.e.ivalue, 12)
+        with self.assertRaises(dm.ReadOnlyField):
+            e.e.ivalue = 14
+        self.assertEqual(e.e.ivalue, 12)
+
+    def test_mutable_object_freeze_nested_element(self):
+        class NElem(dm.Element):
+            ivalue: int = 43
+
+        class E(dm.Element, options=(dm.ObjectMutable)):
+            e: NElem = NElem()
+
+        self.assertEqual(E.e.ivalue, 43)
+        with self.assertRaises(dm.ReadOnlyField):
+            E.e.ivalue = 13
+        self.assertEqual(E.e.ivalue, 43)
+        e = E()
+        self.assertEqual(e.e.ivalue, 43)
+        e.e.ivalue = 14
+        self.assertEqual(e.e.ivalue, 14)
+        e.freeze()
+        self.assertEqual(e.e.ivalue, 14)
+        with self.assertRaises(dm.ReadOnlyField):
+            e.e.ivalue = 15
+        self.assertEqual(e.e.ivalue, 14)
+
+    def test_mutable_object_and_class_freeze_nested_element(self):
+        class NElem(dm.Element):
+            ivalue: int = 43
+
+        class E(dm.Element, options=(dm.ObjectMutable, dm.ClassMutable)):
+            e: NElem = NElem()
+
+        self.assertEqual(E.e.ivalue, 43)
+        E.e.ivalue = 13
+        self.assertEqual(E.e.ivalue, 13)
+        e = E()
+        self.assertEqual(e.e.ivalue, 13)
+        e.e.ivalue = 14
+        self.assertEqual(e.e.ivalue, 14)
+        e.e.freeze()
+        self.assertEqual(e.e.ivalue, 14)
+        with self.assertRaises(dm.ReadOnlyField):
+            e.e.ivalue = 15
+        self.assertEqual(e.e.ivalue, 14)
+
+    def test_element_clone(self):
+        class Elem(dm.Element):
+            ivalue: int = 43
+
+        self.assertTrue(Elem.frozen_cls)
+        self.assertFalse(Elem.mutable_obj)
+
+        e = Elem()
+        print(e)
+
+        new_obj1 = e.clone_as_mutable_variant()
+        self.assertFalse(new_obj1.frozen_cls)
+        self.assertTrue(new_obj1.mutable_obj)
+        self.assertIsInstance(new_obj1, Elem)
+        self.assertEqual(new_obj1.ivalue, 43)
+        new_obj1.ivalue = 55
+        self.assertEqual(new_obj1.ivalue, 55)
+
+        new_obj2 = e.clone_as_mutable_variant()
+        self.assertFalse(new_obj2.frozen_cls)
+        self.assertTrue(new_obj2.mutable_obj)
+        self.assertNotEqual(new_obj1, new_obj2)
+        self.assertEqual(type(new_obj1), type(new_obj2))
+        self.assertEqual(new_obj2.ivalue, 43)
+        new_obj2.ivalue = 56
+        self.assertEqual(new_obj2.ivalue, 56)
+
+        new_obj3 = e.clone_as_mutable_variant()
+        self.assertFalse(new_obj3.frozen_cls)
+        self.assertTrue(new_obj3.mutable_obj)
+        self.assertNotEqual(new_obj1, new_obj3)
+        self.assertNotEqual(new_obj2, new_obj3)
+        self.assertEqual(type(new_obj1), type(new_obj3))
+        self.assertEqual(type(new_obj2), type(new_obj3))
+        self.assertEqual(new_obj3.ivalue, 43)
+        new_obj3.ivalue = 57
+        self.assertEqual(new_obj3.ivalue, 57)
+
+        self.assertEqual(e.ivalue, 43)
+        with self.assertRaises(dm.ReadOnlyField):
+            e.ivalue = 15
+        self.assertEqual(e.ivalue, 43)
+
+        self.assertEqual(new_obj1.ivalue, 55)
+        new_obj1.freeze()
+        self.assertEqual(new_obj1.ivalue, 55)
+        with self.assertRaises(dm.ReadOnlyField):
+            new_obj1.ivalue = 15
+        self.assertEqual(new_obj1.ivalue, 55)
+
+        self.assertEqual(new_obj2.ivalue, 56)
+        self.assertEqual(new_obj3.ivalue, 57)
+        new_obj2.ivalue = 76
+        self.assertEqual(new_obj2.ivalue, 76)
+        self.assertEqual(new_obj3.ivalue, 57)
+        self.assertEqual(new_obj1.ivalue, 55)
+        new_obj2.freeze()
+        self.assertEqual(new_obj2.ivalue, 76)
+        with self.assertRaises(dm.ReadOnlyField):
+            new_obj2.ivalue = 15
+        self.assertEqual(new_obj2.ivalue, 76)
+
+        self.assertTrue(e.frozen)
+        self.assertTrue(new_obj1.frozen)
+        self.assertTrue(new_obj2.frozen)
+        self.assertFalse(new_obj3.frozen)
+
+    def test_element_clone_inheritance(self):
+        class ElemA(dm.Element):
+            ivalue: int = 43
+
+        class ElemB(ElemA):
+            ivalue = 18
+
+        elemA = ElemA()
+        elemB = ElemB()
+
+        _elemA = elemA.clone_as_mutable_variant()
+        _elemB = elemB.clone_as_mutable_variant()
+
+        self.assertIsInstance(elemB, type(elemA))
+        self.assertIsInstance(_elemA, type(elemA))
+        self.assertIsInstance(_elemB, type(elemB))
+        self.assertIsInstance(_elemB, type(_elemA))
+
+    def test_element_clone_inheritance_nested(self):
+        class ElemAInner(dm.Element):
+            fvalue: float = 0.123
+
+        class ElemA(dm.Element):
+            ivalue: int = 43
+            el1: ElemAInner = ElemAInner()
+
+        class ElemBInner(ElemAInner):
+            fvalue = 0.9
+
+        class ElemB(ElemA):
+            ivalue = 18
+            el1 = ElemAInner(fvalue=6.54)
+            el2: ElemBInner = ElemBInner()
+
+        self.assertIsInstance(ElemA.el1, ElemAInner)
+        self.assertIsInstance(ElemB.el1, ElemAInner)
+        self.assertIsInstance(ElemB.el2, ElemAInner)
+        self.assertIsInstance(ElemB.el2, ElemBInner)
+        self.assertNotIsInstance(ElemB.el1, ElemBInner)
+
+        elemA = ElemA()
+        elemB = ElemB()
+
+        _elemA = elemA.clone_as_mutable_variant()
+        _elemB = elemB.clone_as_mutable_variant()
+
+        self.assertIsInstance(elemB, type(elemA))
+        self.assertIsInstance(_elemA, type(elemA))
+        self.assertIsInstance(_elemB, type(elemB))
+        self.assertIsInstance(_elemB, type(_elemA))
+
+        self.assertIsInstance(_elemB.el1, type(_elemA.el1))
+        self.assertIsInstance(_elemA.el1, type(elemA.el1))
+        self.assertIsInstance(_elemB.el1, type(elemB.el1))
+        self.assertIsInstance(_elemB.el1, type(_elemA.el1))
+
+        self.assertIsInstance(_elemB.el2, type(_elemA.el1))
+        self.assertIsInstance(_elemB.el2, type(elemB.el1))
+        self.assertIsInstance(_elemB.el2, type(_elemA.el1))
+
+    def test_element_mutable_invalid_instance_override_container(self):
+        class Elem(dm.Element, options=(dm.ClassMutable, dm.ObjectMutable)):
+            val: list[int] = []
+
+        with self.assertRaises(dm.InvalidFieldValue):
+            Elem(val=["test"])
+
+    def test_element_mutable_invalid_instance_override_container_nested(self):
+        class ElemInner(dm.Element, options=(dm.ClassMutable, dm.ObjectMutable)):
+            val: list[int] = []
+
+        class ElemOuter(dm.Element, options=(dm.ClassMutable, dm.ObjectMutable)):
+            inner: ElemInner = ElemInner()
+
+        # with self.assertRaises(dm.InvalidFieldValue):
+        elem = ElemOuter(inner={"val": [1, 2, 3]})
+
+        self.assertEqual(elem.inner.val, [1, 2, 3])
+
+    def test_class_protocol(self):
+        self.assertIsInstance(dm.base_element.BaseElement, dm.interfaces.FreezableElement)
+
+    def test_wrong_annotated(self):
+
+        with self.assertRaises(dm.UnsupportedFieldType):
+
+            class Elem(dm.Appliance):
+                StrVar: list[Annotated[str, dm.LAMFieldInfo(doc="foo1")]] = ["default value"]
+
+    def test_wrong_annotation_union(self):
+
+        with self.assertRaises(dm.UnsupportedFieldType):
+
+            class Elem(dm.Appliance):
+                StrVar: str | int = "test"
+
+        with self.assertRaises(dm.UnsupportedFieldType):
+
+            class Elem(dm.Appliance):
+                StrVar: list[str | int] = "test"
+
+        with self.assertRaises(dm.UnsupportedFieldType):
+
+            class Elem(dm.Appliance):
+                StrVar: list[None | int] = "test"
+
+    def test_annotation_union(self):
+
+        class Elem(dm.Appliance):
+            strvar1: str | None = "test"
+            strvar1: str | None = None
+            ivar1: Union[int, None] = 12
+            ivar2: Union[int, None] = None
+
+
+# ---------- main ----------
+
+if __name__ == "__main__":
+    unittest.main()

test/test_feature.py

@@ -0,0 +1,830 @@
+# dabmodel (c) by chacha
+#
+# dabmodel  is licensed under a
+# Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International Unported License.
+#
+# You should have received a copy of the license along with this
+# work.  If not, see <https://creativecommons.org/licenses/by-nc-sa/4.0/>.
+
+import unittest
+
+from os import chdir
+from pathlib import Path
+
+from typing import (
+    Any,
+    Annotated,
+)
+
+
+print(__name__)
+print(__package__)
+
+from src import dabmodel as dm
+
+
+testdir_path = Path(__file__).parent.resolve()
+chdir(testdir_path.parent.resolve())
+
+
+def test_initializer_safe_testfc():
+    eval("print('hi')")
+
+
+class FeatureTest(unittest.TestCase):
+    def setUp(self):
+        print("\n->", unittest.TestCase.id(self))
+
+    def immutable_vars__test_field(self, obj: Any, name: str, default_value: Any, test_value: Any):
+        # field is not in the class
+        self.assertNotIn(name, dir(obj.__class__))
+        # field is in the object
+        self.assertIn(name, dir(obj))
+        # field is in the schema
+        self.assertIn(name, obj.__lam_schema__.keys())
+        # field is readable
+        self.assertEqual(getattr(obj, name), default_value)
+        # field is read only
+        with self.assertRaises(dm.ReadOnlyField):
+            setattr(obj, name, test_value)
+
+    def test_simple(self):
+        """Testing first appliance feature, and Field types (simple)"""
+
+        # class can be created
+        class Appliance1(dm.Appliance):
+            VarStrOuter: str = "testvalue APPLIANCE"
+
+            class Feature1(dm.Feature):
+                VarStrInner: str = "testvalue FEATURE"
+
+        app1 = Appliance1()
+
+        self.assertIsInstance(Appliance1.__lam_schema__["VarStrOuter"], dm.LAMField)
+        self.assertTrue(app1.__lam_schema__["VarStrOuter"].is_frozen())
+        self.assertIn("Feature1", app1.__lam_schema__["features"])
+        self.assertIn("VarStrInner", app1.__lam_schema__["features"]["Feature1"].__lam_schema__)
+        self.assertIsInstance(
+            app1.__lam_schema__["features"]["Feature1"].__lam_schema__["VarStrInner"],
+            dm.LAMField,
+        )
+        self.assertTrue(hasattr(app1, "Feature1"))
+        self.assertTrue(app1.Feature1.frozen)
+        print(app1)
+        print(app1.Feature1)
+        print(app1.Feature1.__lam_schema__["VarStrInner"])
+        self.assertTrue(app1.Feature1.__lam_schema__["VarStrInner"].is_frozen())
+        self.assertTrue(hasattr(app1.Feature1, "VarStrInner"))
+
+    def test_inheritance(self):
+        """Testing first appliance feature, and Field types (simple)"""
+
+        # class can be created
+        class Appliance1(dm.Appliance):
+            VarStrOuter: str = "testvalue APPLIANCE1"
+
+            class Feature1(dm.Feature):
+                VarStrInner: str = "testvalue FEATURE1"
+                VarInt: int = 42
+
+        print(dir(Appliance1))
+
+        class Appliance2(Appliance1):
+            VarStrOuter = "testvalue APPLIANCE2"
+
+            class Feature2(dm.Feature):
+                VarStrInner: str = "testvalue FEATURE2"
+
+        print(dir(Appliance2))
+
+        class Appliance3(Appliance2):
+            VarStrOuter = "testvalue APPLIANCE3"
+
+            class Feature1(Appliance1.Feature1):
+                VarStrInner = "testvalue FEATURE1 modded"
+
+            class Feature3(dm.Feature):
+                VarStrInner: str = "testvalue FEATURE3"
+
+        print(dir(Appliance3))
+
+        app1 = Appliance1()
+        app2 = Appliance2()
+        app3 = Appliance3()
+
+        self.assertIsInstance(Appliance1.__lam_schema__["VarStrOuter"], dm.LAMField)
+        self.assertTrue(app1.__lam_schema__["VarStrOuter"].is_frozen())
+        self.assertIn("Feature1", app1.__lam_schema__["features"])
+        self.assertIn("VarStrInner", app1.__lam_schema__["features"]["Feature1"].__lam_schema__)
+        self.assertIsInstance(
+            app1.__lam_schema__["features"]["Feature1"].__lam_schema__["VarStrInner"],
+            dm.LAMField,
+        )
+        self.assertTrue(hasattr(app1, "Feature1"))
+        self.assertTrue(app1.Feature1.__lam_schema__["VarStrInner"].is_frozen())
+        self.assertTrue(hasattr(app1.Feature1, "VarStrInner"))
+        self.assertEqual(app1.VarStrOuter, "testvalue APPLIANCE1")
+        self.assertEqual(app1.Feature1.VarStrInner, "testvalue FEATURE1")
+        self.assertEqual(app1.Feature1.VarInt, 42)
+        self.assertEqual(app2.VarStrOuter, "testvalue APPLIANCE2")
+        self.assertEqual(app2.Feature2.VarStrInner, "testvalue FEATURE2")
+        self.assertEqual(app3.VarStrOuter, "testvalue APPLIANCE3")
+        self.assertEqual(app3.Feature1.VarStrInner, "testvalue FEATURE1 modded")
+        self.assertEqual(app3.Feature1.VarInt, 42)
+        self.assertEqual(app3.Feature3.VarStrInner, "testvalue FEATURE3")
+
+        class Appliance4(Appliance3):
+            VarStrOuter = "testvalue APPLIANCE4"
+
+            class Feature1(Appliance3.Feature1):
+                VarStrInner = "testvalue FEATURE1 modded 3"
+
+    def test_inheritance2(self):
+        """Testing first appliance feature, and Field types (simple)"""
+
+        # class can be created
+        class Appliance1(dm.Appliance):
+            class Feature1(dm.Feature):
+                VarStrInner: str = "testvalue FEATURE1"
+
+        # check cannot REdefine a feature from Feature
+        with self.assertRaises(dm.InvalidFeatureInheritance):
+
+            class Appliance2(Appliance1):
+                class Feature1(dm.Feature): ...
+
+        class Appliance2b(Appliance1):
+            class Feature1(Appliance1.Feature1): ...
+
+        # check only REdefine a feature from highest parent
+        with self.assertRaises(dm.InvalidFeatureInheritance):
+
+            class Appliance3(Appliance2b):
+                class Feature1(Appliance1.Feature1): ...
+
+        class Appliance3b(Appliance2b):
+            class Feature1(Appliance2b.Feature1): ...
+
+        app1 = Appliance1()
+        app2 = Appliance2b()
+        app3 = Appliance3b()
+
+        self.assertEqual(app1.Feature1.VarStrInner, "testvalue FEATURE1")
+        self.assertEqual(app2.Feature1.VarStrInner, "testvalue FEATURE1")
+        self.assertEqual(app3.Feature1.VarStrInner, "testvalue FEATURE1")
+
+        class Appliance4(Appliance3b):
+            class Feature1(Appliance3b.Feature1):
+                VarStrInner = "testvalue FEATURE4"
+
+        self.assertEqual(app1.Feature1.VarStrInner, "testvalue FEATURE1")
+        self.assertEqual(app2.Feature1.VarStrInner, "testvalue FEATURE1")
+        self.assertEqual(app3.Feature1.VarStrInner, "testvalue FEATURE1")
+
+        app4 = Appliance4()
+
+        self.assertEqual(app1.Feature1.VarStrInner, "testvalue FEATURE1")
+        self.assertEqual(app2.Feature1.VarStrInner, "testvalue FEATURE1")
+        self.assertEqual(app3.Feature1.VarStrInner, "testvalue FEATURE1")
+        self.assertEqual(app4.Feature1.VarStrInner, "testvalue FEATURE4")
+
+    def test_inherit_declared(self):
+        class App(dm.Appliance):
+            class F1(dm.Feature):
+                val: int = 1
+
+        class MyF1(App.F1):
+            val = 2
+            val2: str = "toto"
+
+        app = App(F1=MyF1)
+        self.assertIsInstance(app.F1, MyF1)
+        self.assertEqual(app.F1.val, 2)
+        self.assertEqual(app.F1.val2, "toto")
+
+    def test_override_declared(self):
+        class App(dm.Appliance):
+            class F1(dm.Feature):
+                val: int = 1
+                val2: str = "toto"
+
+        app = App(F1={"val": 42, "val2": "tata"})
+        self.assertEqual(app.F1.val, 42)
+        self.assertEqual(app.F1.val2, "tata")
+
+    def test_dict_override_type_error(self):
+        class App(dm.Appliance):
+            class F1(dm.Feature):
+                val: int = 1
+
+        # wrong type for val → must raise InvalidFieldValue
+        with self.assertRaises(dm.InvalidFieldValue):
+            App(F1={"val": "not-an-int"})
+
+    def test_dict_override_nonexisting_field(self):
+        class App(dm.Appliance):
+            class F1(dm.Feature):
+                val: int = 1
+
+        # field does not exist → must raise
+        with self.assertRaises(dm.InvalidFieldValue):
+            App(F1={"doesnotexist": 123})
+
+    def test_inheritance_with_extra_fields(self):
+        class App(dm.Appliance):
+            class F1(dm.Feature):
+                val: int = 1
+
+        class MyF1(App.F1):
+            val = 2
+            extra: str = "hello"
+
+        app = App(F1=MyF1)
+        self.assertEqual(app.F1.val, 2)
+        self.assertEqual(app.F1.extra, "hello")
+
+    def test_override_does_not_leak_between_instances(self):
+        class App(dm.Appliance):
+            class F1(dm.Feature):
+                val: int = 1
+
+        app1 = App(F1={"val": 99})
+        app2 = App()
+        self.assertEqual(app1.F1.val, 99)
+        self.assertEqual(app2.F1.val, 1)
+
+    def test_deepfreeze_nested_mixed_tuple_list(self):
+        class App(dm.Appliance):
+            data: tuple[list[int], tuple[int, list[int]]] = ([1, 2], (3, [4, 5]))
+
+        app = App()
+
+        # Top-level: must be tuple
+        self.assertIsInstance(app.data, tuple)
+
+        # First element of tuple: should have been frozen to tuple, not list
+        self.assertIsInstance(app.data[0], tuple)
+
+        # Nested second element: itself a tuple
+        self.assertIsInstance(app.data[1], tuple)
+
+        # Deepest element: inner list should also be frozen to tuple
+        self.assertIsInstance(app.data[1][1], tuple)
+
+        # Check immutability
+        with self.assertRaises(TypeError):
+            app.data[0] += (99,)  # tuples are immutable
+
+        with self.assertRaises(TypeError):
+            app.data[1][1] += (42,)  # inner tuple also immutable
+
+    def test_inacurate_type(self):
+        with self.assertRaises(dm.InvalidFieldAnnotation):
+
+            class Appliance1(dm.Appliance):
+                SomeVar: list = []
+
+        with self.assertRaises(dm.InvalidFieldAnnotation):
+
+            class Appliance2(dm.Appliance):
+                SomeVar: list[Any] = []
+
+        with self.assertRaises(dm.InvalidFieldAnnotation):
+
+            class Appliance3(dm.Appliance):
+                SomeVar: list[object] = []
+
+        with self.assertRaises(dm.InvalidFieldAnnotation):
+
+            class Appliance4(dm.Appliance):
+                SomeVar: dict = {}
+
+        with self.assertRaises(dm.InvalidFieldAnnotation):
+
+            class Appliance5(dm.Appliance):
+                SomeVar: dict[str, Any] = {}
+
+        with self.assertRaises(dm.InvalidFieldAnnotation):
+
+            class Appliance6(dm.Appliance):
+                SomeVar: dict[Any, Any] = {}
+
+        with self.assertRaises(dm.InvalidFieldAnnotation):
+
+            class Appliance7(dm.Appliance):
+                SomeVar: dict[Any, str] = {}
+
+        with self.assertRaises(dm.InvalidFieldAnnotation):
+
+            class Appliance8(dm.Appliance):
+                SomeVar: dict[str, object] = {}
+
+    def test_cant_override_inherited_annotation(self):
+        class App(dm.Appliance):
+            class F1(dm.Feature):
+                val: int = 1
+
+        with self.assertRaises(dm.ReadOnlyFieldAnnotation):
+
+            class Extra(App.F1):
+                val: str = "test"
+
+    def test_fields_are_frozen_after_override(self):
+        class App(dm.Appliance):
+            class F(dm.Feature):
+                nums: list[int] = [1, 2]
+                tag: str = "x"
+
+        # dict override
+        app1 = App(F={"nums": [9], "tag": "y"})
+        self.assertEqual(app1.F.nums, (9,))
+        self.assertEqual(app1.F.tag, "y")
+        with self.assertRaises(AttributeError):
+            app1.F.nums.append(3)  # tuple
+
+        # subclass override
+        class F2(App.F):
+            nums = [4, 5]
+
+        app2 = App(F=F2)
+        self.assertEqual(app2.F.nums, (4, 5))
+        with self.assertRaises(dm.ReadOnlyField):
+            app2.F.nums += (6,)  # still immutable
+
+    def test_dict_partial_override_keeps_other_defaults(self):
+        class App(dm.Appliance):
+            class F(dm.Feature):
+                a: int = 1
+                b: str = "k"
+
+        app = App(F={"b": "z"})
+        self.assertEqual(app.F.a, 1)  # default remains
+        self.assertEqual(app.F.b, "z")  # overridden
+
+    def test_override_linear_chain(self):
+        # Base appliance defines Feat1
+        class A(dm.Appliance):
+            class Feat1(dm.Feature):
+                x: int = 1
+
+        # ✅ Appliance B overrides Feat1 by subclassing A.Feat1
+        class B(A):
+            class Feat1(A.Feat1):
+                y: int = 2
+
+        self.assertTrue(issubclass(B.Feat1, A.Feat1))
+
+        # ✅ Appliance C overrides Feat1 again by subclassing B.Feat1 (not A.Feat1)
+        class C(B):
+            class Feat1(B.Feat1):
+                z: int = 3
+
+        self.assertTrue(issubclass(C.Feat1, B.Feat1))
+        self.assertTrue(issubclass(C.Feat1, A.Feat1))
+
+        # ❌ Bad: D tries to override with a *fresh* Feature, not subclass of B.Feat1
+        with self.assertRaises(dm.InvalidFeatureInheritance):
+
+            class D(B):
+                class Feat1(dm.Feature):
+                    fail: str = "oops"
+
+        # ❌ Bad: E tries to override with ancestor (A.Feat1) instead of B.Feat1
+        with self.assertRaises(dm.InvalidFeatureInheritance):
+
+            class E(B):
+                class Feat1(A.Feat1):
+                    fail: str = "oops"
+
+        # ✅ New feature name in child is always fine
+        class F(B):
+            class Feat2(dm.Feature):
+                other: str = "ok"
+
+        self.assertTrue(hasattr(F, "Feat2"))
+
+    def test_override_chain_runtime_replacement(self):
+        # Build a linear chain: A -> B -> C for feature 'Feat1'
+        class A(dm.Appliance):
+            class Feat1(dm.Feature):
+                x: int = 1
+
+        class B(A):
+            class Feat1(A.Feat1):
+                y: int = 2
+
+        class C(B):
+            class Feat1(B.Feat1):
+                z: int = 3
+
+        # ✅ OK: at instantiation of C, replacing Feat1 with a subclass of the LATEST (C.Feat1)
+        class CFeat1Plus(C.Feat1):
+            w: int = 4
+
+        c_ok = C(Feat1=CFeat1Plus)
+        self.assertIsInstance(c_ok.Feat1, CFeat1Plus)
+        self.assertEqual((c_ok.Feat1.x, c_ok.Feat1.y, c_ok.Feat1.z, c_ok.Feat1.w), (1, 2, 3, 4))
+
+        # ❌ Not OK: replacing with a subclass of the ancestor (A.Feat1) — must target latest (C.Feat1)
+        class AFeat1Alt(A.Feat1):
+            pass
+
+        with self.assertRaises(dm.InvalidFieldValue):
+            C(Feat1=AFeat1Alt)
+
+        # ❌ Not OK: replacing with a subclass of the mid ancestor (B.Feat1) — still must target latest (C.Feat1)
+        class BFeat1Alt(B.Feat1):
+            pass
+
+        with self.assertRaises(dm.InvalidFieldValue):
+            C(Feat1=BFeat1Alt)
+
+    def test_inheritance_tree_and_no_leakage(self):
+        class A(dm.Appliance):
+            class F1(dm.Feature):
+                a: int = 1
+
+            class F2(dm.Feature):
+                b: int = 2
+
+        # ✅ Child inherits both features automatically
+        class B(A):
+            c: str = "extra"
+
+        b1 = B()
+        self.assertIsInstance(b1.F1, A.F1)
+        self.assertIsInstance(b1.F2, A.F2)
+        self.assertEqual((b1.F1.a, b1.F2.b, b1.c), (1, 2, "extra"))
+
+        # ✅ Override only F2, F1 should still come from A
+        class C(B):
+            class F2(B.F2):
+                bb: int = 22
+
+        c1 = C()
+        self.assertIsInstance(c1.F1, A.F1)  # unchanged
+        self.assertIsInstance(c1.F2, C.F2)  # overridden
+        self.assertEqual((c1.F1.a, c1.F2.b, c1.F2.bb), (1, 2, 22))
+
+        # ✅ No leakage: instances of B are not affected by C's override
+        b2 = B()
+        self.assertIsInstance(b2.F2, A.F2)
+        self.assertFalse(hasattr(b2.F2, "bb"))
+
+        # ✅ Adding a new feature in D is independent of previous appliances
+        class D(C):
+            class F3(dm.Feature):
+                d: int = 3
+
+        d1 = D()
+        self.assertIsInstance(d1.F1, A.F1)
+        self.assertIsInstance(d1.F2, C.F2)
+        self.assertIsInstance(d1.F3, D.F3)
+
+        # ✅ No leakage: instances of A and B should not see F3
+        a1 = A()
+        self.assertFalse(hasattr(a1, "F3"))
+        b3 = B()
+        self.assertFalse(hasattr(b3, "F3"))
+
+    def test_appliance_inheritance_tree_isolation(self):
+        class A(dm.Appliance):
+            class F1(dm.Feature):
+                a: int = 1
+
+        # Branch 1 overrides F1
+        class B(A):
+            class F1(A.F1):
+                b: int = 2
+
+        # Branch 2 also overrides F1 differently
+        class C(A):
+            class F1(A.F1):
+                c: int = 3
+
+        # ✅ Instances of B use B.F1
+        b = B()
+        self.assertIsInstance(b.F1, B.F1)
+        print(b.F1)
+        print(dir(b.F1))
+        self.assertEqual((b.F1.a, b.F1.b), (1, 2))
+        self.assertFalse(hasattr(b.F1, "c"))
+
+        # ✅ Instances of C use C.F1
+        c = C()
+        self.assertIsInstance(c.F1, C.F1)
+        self.assertEqual((c.F1.a, c.F1.c), (1, 3))
+        self.assertFalse(hasattr(c.F1, "b"))
+
+        # ✅ Base appliance A still uses its original feature
+        a = A()
+        self.assertIsInstance(a.F1, A.F1)
+        self.assertEqual(a.F1.a, 1)
+        self.assertFalse(hasattr(a.F1, "b"))
+        self.assertFalse(hasattr(a.F1, "c"))
+
+        # ✅ No leakage: B's override doesn't affect C and vice versa
+        b2 = B()
+        c2 = C()
+        self.assertTrue(hasattr(b2.F1, "b"))
+        self.assertFalse(hasattr(b2.F1, "c"))
+        self.assertTrue(hasattr(c2.F1, "c"))
+        self.assertFalse(hasattr(c2.F1, "b"))
+
+    def test_appliance_inheritance_tree_runtime_attach_isolation(self):
+        class A(dm.Appliance):
+            class F1(dm.Feature):
+                a: int = 1
+
+        class B(A):
+            class F1(A.F1):
+                b: int = 2
+
+        class C(A):
+            class F1(A.F1):
+                c: int = 3
+
+        # Define new runtime-attachable features
+        class FextraB(B.F1):
+            xb: int = 99
+
+        class FextraC(C.F1):
+            xc: int = -99
+
+        # ✅ Attach to B at instantiation
+        b = B(F1=FextraB)
+        self.assertIsInstance(b.F1, FextraB)
+        self.assertEqual((b.F1.a, b.F1.b, b.F1.xb), (1, 2, 99))
+        self.assertFalse(hasattr(b.F1, "c"))
+        self.assertFalse(hasattr(b.F1, "xc"))
+
+        # ✅ Attach to C at instantiation
+        c = C(F1=FextraC)
+        self.assertIsInstance(c.F1, FextraC)
+        self.assertEqual((c.F1.a, c.F1.c, c.F1.xc), (1, 3, -99))
+        self.assertFalse(hasattr(c.F1, "b"))
+        self.assertFalse(hasattr(c.F1, "xb"))
+
+        # ✅ Base appliance still untouched
+        a = A()
+        self.assertIsInstance(a.F1, A.F1)
+        self.assertEqual(a.F1.a, 1)
+        self.assertFalse(hasattr(a.F1, "b"))
+        self.assertFalse(hasattr(a.F1, "c"))
+        self.assertFalse(hasattr(a.F1, "xb"))
+        self.assertFalse(hasattr(a.F1, "xc"))
+
+        # ✅ Repeated instantiations stay isolated
+        b2 = B()
+        c2 = C()
+        self.assertIsInstance(b2.F1, B.F1)
+        self.assertIsInstance(c2.F1, C.F1)
+        self.assertFalse(hasattr(b2.F1, "xb"))
+        self.assertFalse(hasattr(c2.F1, "xc"))
+
+    def test_feature_dict_override_with_nested_containers(self):
+        class App(dm.Appliance):
+            class F1(dm.Feature):
+                values: list[int] = [1, 2]
+
+        app = App(F1={"values": [5, 6]})
+        self.assertEqual(app.F1.values, (5, 6))  # deepfreeze → tuple
+
+        # Invalid type in list should fail
+        with self.assertRaises(dm.InvalidFieldValue):
+            App(F1={"values": [1, "oops"]})
+
+    def test_dict_override_with_unknown_key(self):
+        class App(dm.Appliance):
+            class F1(dm.Feature):
+                a: int = 1
+
+        # Dict override with unknown field 'zzz'
+        with self.assertRaises(dm.InvalidFieldValue):
+            App(F1={"zzz": 42})
+
+    def test_schema_isolation_across_multiple_overrides(self):
+        class App(dm.Appliance):
+            class F1(dm.Feature):
+                a: int = 1
+
+        class F1a(App.F1):
+            a = 10
+
+        class F1b(App.F1):
+            a = 20
+
+        app1 = App(F1=F1a)
+        self.assertIsInstance(app1.F1, F1a)
+        self.assertEqual(app1.F1.a, 10)
+
+        app2 = App(F1=F1b)
+        self.assertIsInstance(app2.F1, F1b)
+        self.assertEqual(app2.F1.a, 20)
+
+        # Original appliance schema must not be polluted
+        app3 = App()
+        self.assertIsInstance(app3.F1, App.F1)
+        self.assertEqual(app3.F1.a, 1)
+
+    def test_inheritance_with_annotated_fields(self):
+
+        class App(dm.Appliance):
+            class F1(dm.Feature):
+                a: Annotated[int, dm.LAMFieldInfo(doc="field a")] = 1
+
+        # ✅ Subclass override must inherit from parent F1
+        class F1Ex(App.F1):
+            b: str = "ok"
+
+        app = App(F1=F1Ex)
+        self.assertIsInstance(app.F1, F1Ex)
+        self.assertEqual((app.F1.a, app.F1.b), (1, "ok"))
+
+        # ❌ Wrong: fresh Feature under same name
+        with self.assertRaises(dm.InvalidFeatureInheritance):
+
+            class Bad(App):
+                class F1(dm.Feature):
+                    fail: str = "oops"
+
+    def test_initializer(self):
+        class App(dm.Appliance):
+            integ: int = 18
+
+            class F(dm.Feature):
+                nums: list[int] = [1, 2]
+                tag: str = "x"
+
+            @classmethod
+            def __initializer(cls):
+                cls.F.tag = "test"
+                cls.F.nums.append(3)
+
+        self.assertEqual(App.F.tag, "test")
+        self.assertEqual(App.F.nums, (1, 2, 3))
+
+    def test_initializer_nested(self):
+        class App(dm.Appliance):
+            integ: int = 18
+
+            class F(dm.Feature):
+                nums: list[int] = [1, 2]
+                tag: str = "x"
+
+                @classmethod
+                def __initializer(cls):
+                    cls.tag = "test"
+                    cls.nums.append(3)
+
+        self.assertEqual(App.F.tag, "test")
+        self.assertEqual(App.F.nums, (1, 2, 3))
+
+    def test_initializer_nested_dual(self):
+        class App(dm.Appliance):
+            integ: int = 18
+
+            class F(dm.Feature):
+                nums: list[int] = [1, 2]
+                tag: str = "x"
+
+                @classmethod
+                def __initializer(cls):
+                    cls.tag = "test1"
+                    cls.nums.append(3)
+
+            @classmethod
+            def __initializer(cls):
+                cls.F.tag = "test2"
+                cls.F.nums.append(4)
+
+        self.assertEqual(App.F.tag, "test2")
+        self.assertEqual(App.F.nums, (1, 2, 3, 4))
+
+    def test_container_frozen(self):
+        class App(dm.Appliance):
+            integ: int = 18
+
+            class F(dm.Feature):
+                nums: list[int] = [1, 2]
+                tag: str = "x"
+
+        with self.assertRaises(AttributeError):
+            App.F.nums.append(3)
+
+    def test_container_class_mutable_validation(self):
+        class App(dm.Appliance, options=(dm.ClassMutable)):
+            integ: int = 18
+
+            class F(dm.Feature):
+                nums: list[int] = [1, 2]
+                tag: str = "x"
+
+        App.F.nums.append("test")
+
+        with self.assertRaises(dm.InvalidFieldValue):
+            App.freeze_class()
+
+        with self.assertRaises(dm.InvalidFieldValue):
+            a = App()
+
+    def test_container_object_mutable_validation(self):
+        class App(dm.Appliance, options=(dm.ObjectMutable)):
+            integ: int = 18
+
+            class F(dm.Feature):
+                nums: list[int] = [1, 2]
+                tag: str = "x"
+
+        a = App()
+        a.F.nums.append("test")
+
+        with self.assertRaises(dm.InvalidFieldValue):
+            a.freeze()
+
+    def test_container_object_and_class_mutable_validation(self):
+        class App(dm.Appliance, options=(dm.ClassMutable, dm.ObjectMutable)):
+            integ: int = 18
+
+            class F(dm.Feature):
+                nums: list[int] = [1, 2]
+                tag: str = "x"
+
+        App.F.nums.append("test")
+
+        with self.assertRaises(dm.InvalidFieldValue):
+            a = App()
+
+        with self.assertRaises(dm.InvalidFieldValue):
+            App.freeze_class()
+
+    def test_nested_element_container_object_and_class_mutable(self):
+        class E(dm.Element):
+            val: str = "testelem"
+            i: list[int] = [1]
+
+        class App(dm.Appliance, options=(dm.ClassMutable, dm.ObjectMutable)):
+            integ: int = 18
+
+            class F(dm.Feature):
+                nums: list[int] = [1, 2]
+                tag: str = "x"
+                e: E = E(val="modified")
+
+        App.F.e.i.append(21)
+        self.assertEquals(App.F.e.i, [1, 21])
+        App.freeze_class()
+        with self.assertRaises(AttributeError):
+            App.F.e.i.append(22)
+        a = App()
+        self.assertEquals(a.F.e.i, [1, 21])
+        a.F.e.i.append(28)
+        self.assertEquals(a.F.e.i, [1, 21, 28])
+        a.freeze()
+        self.assertEquals(a.F.e.i, (1, 21, 28))
+        with self.assertRaises(AttributeError):
+            a.F.e.i.append(23)
+        self.assertEquals(a.F.e.i, (1, 21, 28))
+
+    def test_nested_element_container_object_and_class_mutable_validation(self):
+        class E(dm.Element):
+            val: str = "testelem"
+            i: list[int] = [1]
+
+        class App(dm.Appliance, options=(dm.ClassMutable, dm.ObjectMutable)):
+            integ: int = 18
+
+            class F(dm.Feature):
+                nums: list[int] = [1, 2]
+                tag: str = "x"
+                e: E = E(val="modified")
+
+        App.F.e.i.append("test")
+
+        with self.assertRaises(dm.InvalidFieldValue):
+            a = App()
+
+    def test_nested_element_container_object_and_class_mutable_validation2(self):
+        class E(dm.Element):
+            val: str = "testelem"
+            i: list[int] = [1]
+
+        class App(dm.Appliance, options=(dm.ClassMutable, dm.ObjectMutable)):
+            integ: int = 18
+
+            class F(dm.Feature):
+                nums: list[int] = [1, 2]
+                tag: str = "x"
+                e: E = E(val="modified")
+
+        a = App()
+        a.F.e.i.append("test")
+
+        with self.assertRaises(dm.InvalidFieldValue):
+            a.freeze()
+
+
+# ---------- main ----------
+
+if __name__ == "__main__":
+    unittest.main()

test/test_feature_bind.py

@@ -0,0 +1,166 @@
+# dabmodel (c) by chacha
+#
+# dabmodel  is licensed under a
+# Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International Unported License.
+#
+# You should have received a copy of the license along with this
+# work.  If not, see <https://creativecommons.org/licenses/by-nc-sa/4.0/>.
+
+import unittest
+
+from os import chdir
+from pathlib import Path
+
+from typing import (
+    Any,
+    Annotated,
+)
+from dabmodel.appliance import Appliance
+
+
+print(__name__)
+print(__package__)
+
+from src import dabmodel as dm
+
+
+testdir_path = Path(__file__).parent.resolve()
+chdir(testdir_path.parent.resolve())
+
+
+def test_initializer_safe_testfc():
+    eval("print('hi')")
+
+
+class FeatureBindTest(unittest.TestCase):
+    def setUp(self):
+        print("\n->", unittest.TestCase.id(self))
+
+    def test_simple(self):
+        """Testing first appliance feature, and Field types (simple)"""
+
+        # class can be created
+        class Appliance1(dm.Appliance):
+            VarStrOuter: str = "testvalue APPLIANCE"
+
+            class Feature1(dm.Feature):
+                VarStrInner: str = "testvalue FEATURE"
+
+        app1 = Appliance1()
+
+        self.assertIn("Feature1", app1.__lam_schema__["features"])
+        self.assertTrue(hasattr(app1, "Feature1"))
+
+    def test_outside_bind(self):
+        """Testing first appliance feature, and Field types (simple)"""
+
+        # class can be created
+        class Appliance1(dm.Appliance):
+            pass
+
+        class Feature1(dm.Feature, appliance=Appliance1):
+            VarStrInner: str = "testvalue FEATURE1"
+
+        app = Appliance1(feat1=Feature1)
+        self.assertEqual(app.feat1.VarStrInner, "testvalue FEATURE1")
+
+        # check it does not leak accross instances
+
+        app = Appliance1(feat2=Feature1)
+        self.assertEqual(app.feat2.VarStrInner, "testvalue FEATURE1")
+
+        with self.assertRaises(AttributeError):
+            app.feat1
+
+    def test_outside_bind2(self):
+        """Testing first appliance feature, and Field types (simple)"""
+
+        # class can be created
+        class Appliance1(dm.Appliance):
+            pass
+
+        class Feature1(dm.Feature):
+            VarStrInner: str = "testvalue FEATURE1"
+
+        Feature1.bind_appliance(Appliance1)
+
+        app = Appliance1(feat1=Feature1)
+        self.assertEqual(app.feat1.VarStrInner, "testvalue FEATURE1")
+
+        # check it does not leak accross instances
+
+        app = Appliance1(feat2=Feature1)
+        self.assertEqual(app.feat2.VarStrInner, "testvalue FEATURE1")
+
+        with self.assertRaises(AttributeError):
+            app.feat1
+
+    def test_bind_inheritance_no_leak(self):
+        """Testing first appliance feature, and Field types (simple)"""
+
+        # class can be created
+        class Appliance1(dm.Appliance):
+            pass
+
+        class Feature1(dm.Feature):
+            VarStrInner: str = "testvalue FEATURE1"
+
+        class Feature2(Feature1, appliance=Appliance1):
+            VarStrInner = "testvalue FEATURE2"
+
+        app = Appliance1(feat=Feature2)
+        self.assertEqual(app.feat.VarStrInner, "testvalue FEATURE2")
+
+        with self.assertRaises(dm.FeatureNotBound):
+            app = Appliance1(feat=Feature1)
+
+    def test_bind_notbound(self):
+        """Testing first appliance feature, and Field types (simple)"""
+
+        # class can be created
+        class Appliance1(dm.Appliance):
+            pass
+
+        class Feature1(dm.Feature):
+            VarStrInner: str = "testvalue FEATURE1"
+
+        with self.assertRaises(dm.FeatureNotBound):
+            Appliance1(feat1=Feature1)
+
+    def test_bind_defect(self):
+
+        class Feature1(dm.Feature):
+            pass
+
+        with self.assertRaises(dm.FeatureNotBound):
+            Feature1()
+
+    def test_not_bound_runtime_attach_fails(self):
+        class App(dm.Appliance):
+            pass
+
+        class UnboundFeature(dm.Feature):
+            x: int = 1
+
+        # attaching an unbound feature should raise
+        with self.assertRaises(dm.FeatureNotBound):
+            App(Unbound=UnboundFeature)
+
+    def test_runtime_attach_bound_success(self):
+        class App(dm.Appliance):
+            class F1(dm.Feature):
+                val: int = 1
+
+        class Extra(App.F1):  # stays bound to App
+            val = 7
+
+        app = App(Extra=Extra)
+        self.assertTrue(hasattr(app, "Extra"))
+        self.assertIsInstance(app.Extra, Extra)
+        self.assertEqual(app.Extra.val, 7)
+
+
+# ---------- main ----------
+
+if __name__ == "__main__":
+    unittest.main()