All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

• Removed dependency on sentinel-value.

• Dropped support for Python 3.8 & 3.9.

• Component key type-hints now use TypeForm. Complex component types which already worked at runtime are now recognized by type linters.

Maintenance release

• Allow setting the traverse state of an entity.component_tags[type][entity](traverse=...) attribute.

• Updated deprecations to use PEP 702.

• Fixed .clear methods for entity.components and entity.component_relations.

• New query .any_of method. This was possible before but it is easier with this method.

• Clearing an entity with inherited components no longer leaves the entity with missed components.

• Clearing an entity with inherited tags no longer hangs.

• EntityComponents.pop now correctly returns defaults when the components are inherited instead of local.

• Fixed type of default parameter for EntityComponents.get.

• Queries are now truthy if they match any entity.

• Renamed World to the more standard name Registry in multiple places.

• World is now Registry
• WorldQuery is now BoundQuery
• .world attributes of Entity and BoundQuery are now .registry

• Updated EntityComponents.__ior__ type hints which were causing false positives.

• Added the tcod.ecs.IsA sentinel value.
• Entities will automatically inherit components/tags/relations from entities they have an IsA relationship with. #15
• Entities can be used as prefabs, use Entity.instantiate() to make a new entities inheriting the base entities components/tags/relations.

• tcod.ecs.query.Query removed due to a refactor.
• abstract_component decorator removed.

• Fix for x in Entity.relation_tags_many not checking the correct values.

• Added WorldQuery.get_entities for returning query results as a set.

• Removed an optimization which would check the equality of component values, since this would fail when comparing some types such as NumPy arrays.
• Removed unintentional iteration behavior from World. #8

• Relation component lookup tables were replacing previous entries instead of adding to them.
• Relation ellipsis lookup tables were discarding entities which still had a relevant relation.

• tcod.ecs.typing.ComponentKey is now stable.
• Can now register a callback to be called on component changes.

• Fixed stale caches for relation components.

• Unpickled worlds had reversed relations from what were saved.

• Entity.relation_components now has MutableMapping functionality.
• You can now set the value of Entity.relation_components[component_key] = {target: component}.
• Added the Entity.clear method which effectively deletes an entity by removing its components/tags/relations. This does not delete relations targeting the cleared entity.

• Now supports giving a query to another relation query, allowing conditional and chained relation queries. #1

• The type returned by World.Q has been renamed from tcod.ecs.Query to tcod.ecs.query.WorldQuery.
• Serialization format updated.

• Added a simple query cache. A query is automatically cached until any of the components/tags/relations it depends on have changed.

• Serialization format updated, older versions will not be able to unpickle this version.
• Reduced the size of the pickled World.

• Missing components in Entity.components now returns the missing key in the KeyError exception instead of the entity.
• Backwards relations for querying were not cleared on relation deletions.

• Entity.components now supports the |= assignment operator.

• Entity.tags now supports the |= and -= assignment operators.

• Warn if a string is passed directly as a tags parameter, which might cause unexpected behavior.
• Entity.relation_tags has been renamed to Entity.relation_tag.

• Deprecated the renamed attribute Entity.relation_tag.

• World.new_entity can now take a Mapping as the components parameter.

• Implicit keys for components have been deprecated in all places.
• The names feature has been deprecated.
• Entity.components.by_name_type has been deprecated.

• World.global_ has been deprecated since world[None] is simpler and less redundant.

• Entity.components.by_name_type(name_type, component_type) to iterate over named components with names of a specific type.

• Remap World.global_ to uid=None.

• You can now use custom identifiers for entity objects. You can access these from World instances with entity = world[uid].

• Dropped support for unpickling v1.0 World objects.

• Allow Entity instances to be referenced weakly.

• Added missing typing marker.
• Corrected the type-hinting of Entity.component.get and Entity.component.setdefault.

• World's now have a globally accessible entity accessed with World.global_.

• You can now quickly lookup the relation tags and relation component keys of an entity.

First stable release.