Apply dataclass transform to AtomMeta

atom/api.py

@@ -40,6 +40,7 @@
     MissingMemberWarning,
     add_member,
     clone_if_needed,
+    member,
     observe,
     set_default,
 )
@@ -119,6 +120,7 @@
     "cached_property",
     "clone_if_needed",
     "defaultatomdict",
+    "member",
     "observe",
     "set_default",
 ]

atom/catom.pyi

@@ -5,6 +5,7 @@
 #
 # The full license is in the file LICENSE, distributed with this software.
 # --------------------------------------------------------------------------------------
+import sys
 from enum import IntEnum, IntFlag
 from typing import (
     Any,
@@ -22,7 +23,10 @@ from typing import (
     overload,
 )
 
-from typing_extensions import Self
+if sys.version_info < (3, 11):
+    from typing_extensions import Self
+else:
+    from typing import Self
 
 from .atom import Atom
 from .property import Property

atom/meta/__init__.py

@@ -8,14 +8,16 @@
 """Atom metaclass and tools used to create atom subclasses."""
 
 from .atom_meta import AtomMeta, MissingMemberWarning, add_member, clone_if_needed
-from .member_modifiers import set_default
+from .member_modifiers import member, set_default
 from .observation import observe
 
 __all__ = [
     "AtomMeta",
     "MissingMemberWarning",
     "add_member",
     "clone_if_needed",
+    "member",
     "observe",
     "set_default",
+    "set_default",
 ]

atom/meta/annotation_utils.py

@@ -10,17 +10,28 @@
 from typing import Any, ClassVar, Literal, MutableMapping, Type
 
 from ..catom import Member
+from ..coerced import Coerced
 from ..dict import DefaultDict, Dict as ADict
 from ..enum import Enum
 from ..instance import Instance
 from ..list import List as AList
-from ..scalars import Bool, Bytes, Callable as ACallable, Float, Int, Str, Value
+from ..scalars import (
+    Bool,
+    Bytes,
+    Callable as ACallable,
+    Constant,
+    Float,
+    Int,
+    ReadOnly,
+    Str,
+    Value,
+)
 from ..set import Set as ASet
 from ..subclass import Subclass
 from ..tuple import FixedTuple, Tuple as ATuple
 from ..typed import Typed
 from ..typing_utils import extract_types, get_args, get_origin, is_optional
-from .member_modifiers import set_default
+from .member_modifiers import _SENTINEL, member
 
 _NO_DEFAULT = object()
 
@@ -38,8 +49,11 @@
     collections.abc.Callable: ACallable,
 }
 
+# XXX handle member as annotation
+# XXX handle str as annotation with default
 
-def generate_member_from_type_or_generic(
+
+def generate_member_from_type_or_generic(  # noqa C901
     type_generic: Any, default: Any, annotate_type_containers: int
 ) -> Member:
     """Generate a member from a type or generic alias."""
@@ -51,16 +65,30 @@
         types = extract_types(type_generic)
     parameters = get_args(type_generic)
 
-    m_kwargs = {}
+    m_kwargs: dict[str, Any] = {}
 
     m_cls: Type[Member]
     if any(
         isinstance(t, type) and issubclass(t, Member) for t in types
-    ) and not isinstance(default, Member):
+    ) and not isinstance(default, (Member, member)):
         raise ValueError(
             "Member subclasses cannot be used as annotations without "
             "specifying a default value for the attribute."
         )
+    elif isinstance(default, member) and any(
+        (default._constant, default._coercer, default._read_only)
+    ):
+        if default._coercer is not None:
+            m_cls = Coerced
+            parameters = (types,)
+            m_kwargs["coercer"] = default._coercer
+        if default._read_only:
+            m_cls = ReadOnly
+            parameters = (types,)
+        if default._constant:
+            m_cls = Constant
+            m_kwargs["kind"] = types
+
     elif object in types or Any in types:
         m_cls = Value
         parameters = ()
@@ -124,22 +152,41 @@
 
         parameters = (filtered_types,)
         m_kwargs["optional"] = opt
-        if opt and default not in (_NO_DEFAULT, None):
+        if (
+            opt
+            and not isinstance(default, member)
+            and default not in (_NO_DEFAULT, None)
+        ):
             raise ValueError(
                 "Members requiring Instance(optional=True) cannot have "
                 "a non-None default value."
             )
-        elif not opt and default is not _NO_DEFAULT:
+        elif not opt and not isinstance(default, member) and default is not _NO_DEFAULT:
             raise ValueError("Members requiring Instance cannot have a default value.")
 
         # Instance does not have a default keyword so turn a None default into the
         # equivalent no default.
-        default = _NO_DEFAULT
+        if default is None:
+            default = _NO_DEFAULT
 
-    if default is not _NO_DEFAULT:
+    if isinstance(default, member):
+        if default.default_value is not _SENTINEL:
+            m_kwargs["default"] = default.default_value
+        elif default.default_factory is not None:
+            m_kwargs["factory"] = default.default_factory
+        if default.default_args is not None:
+            m_kwargs["args"] = default.default_args
+        if default.default_kwargs is not None:
+            m_kwargs["kwargs"] = default.default_kwargs
+
+    elif default is not _NO_DEFAULT:
         m_kwargs["default"] = default
 
-    return m_cls(*parameters, **m_kwargs)
+    new = m_cls(*parameters, **m_kwargs)
+    if isinstance(default, member) and default.metadata:
+        new.metadata = default.metadata
+
+    return new
 
 
 def generate_members_from_cls_namespace(
@@ -153,7 +200,7 @@
 
         # We skip field for which a member was already provided or annotations
         # corresponding to class variables.
-        if isinstance(default, (Member, set_default)):
+        if isinstance(default, Member):
             # Allow string annotations for members
             if isinstance(ann, str):
                 continue