Entities

An entity is anything that can be referred to: a character, a group, a place, an object. Each has an entity type, which declares its fields and its kind:

• agent: can hold knowledge (a person, an NPC, a reader);
• group: can hold knowledge of its own (a guild, a council, a party);
• other: can be talked about but holds nothing (a place, an object).

An entity may carry an external reference ({ system, id }), the id another system gives it, so a game or an app can register and find its own characters by their ids (entity.ensureBatch, entity.resolve).