Relation traversal and propagation

CHANGELOG.md

@@ -6,8 +6,17 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Added
+- Added the `tcod.ecs.IsA` sentinel value.
+- Entities will automatically inherit components/tags/relations from entities they have an `IsA` relationship with. https://github.com/HexDecimal/python-tcod-ecs/pull/15
+- Entities can be used as prefabs, use `Entity.instantiate()` to make a new entities inheriting the base entities components/tags/relations.
+
 ### Removed
 - `tcod.ecs.query.Query` removed due to a refactor.
+- `abstract_component` decorator removed.
+
+### Fixed
+- Fix for `x in Entity.relation_tags_many` not checking the correct values.
 
 ## [4.4.0] - 2023-08-11
 ### Added

docs/api.rst

@@ -27,6 +27,11 @@ API reference
    :undoc-members:
    :show-inheritance:
 
+.. automodule:: tcod.ecs.constants
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
 .. automodule:: tcod.ecs.typing
    :members:
    :undoc-members:

pyproject.toml

@@ -18,7 +18,12 @@ classifiers = [
 ]
 dynamic = ["version", "description"]
 requires-python = ">=3.8"
-dependencies = ["typing-extensions >=4.4.0", "attrs>=23.1.0", "cattrs>=23.1.2"]
+dependencies = [
+    "attrs >=23.1.0",
+    "cattrs >=23.1.2",
+    "sentinel-value >=1.0.0",
+    "typing-extensions >=4.4.0",
+]
 
 [tool.setuptools_scm]
 write_to = "tcod/ecs/_version.py"

tcod/ecs/__init__.py

@@ -2,18 +2,18 @@
 from __future__ import annotations
 
 import importlib.metadata
-import warnings
 from collections import defaultdict
 from typing import TypeVar
 
+from tcod.ecs.constants import IsA
 from tcod.ecs.entity import Entity
 from tcod.ecs.world import World
 
 __all__ = (
     "__version__",
     "Entity",
+    "IsA",
     "World",
-    "abstract_component",
 )
 
 try:
@@ -22,27 +22,11 @@
     __version__ = ""
 
 
-T = TypeVar("T")
 _T1 = TypeVar("_T1")
 _T2 = TypeVar("_T2")
 _T3 = TypeVar("_T3")
 
 
-def abstract_component(cls: type[T]) -> type[T]:
-    """Register class `cls` as an abstract component and return it.
-
-    .. deprecated:: 3.1
-        This decorator is deprecated since abstract components should always be explicit.
-    """
-    warnings.warn(
-        "This decorator is deprecated since abstract components should always be explicit.",
-        FutureWarning,
-        stacklevel=2,
-    )
-    cls._TCOD_BASE_COMPONENT = cls  # type: ignore[attr-defined]
-    return cls
-
-
 def _defaultdict_of_set() -> defaultdict[_T1, set[_T2]]:  # Migrate from <=3.4
     """Return a new defaultdict of sets."""
     return defaultdict(set)

tcod/ecs/constants.py

@@ -0,0 +1,7 @@
+"""Special constants and sentinel values."""
+from typing import Final
+
+from sentinel_value import sentinel
+
+IsA: Final = sentinel("IsA")
+"""The default is-a relationship tag used for entity inheritance."""