update everything except for IdType to operate off of EntityType rather than EntityDescription. This feels much more natural.

Examples.swift

@@ -7,10 +7,12 @@
 
 import JSONAPI
 
+typealias StringId<E: EntityDescription> = Id<String, E>
+
 enum PersonDescription: IdentifiedEntityDescription {
-	static var type: String { return "people" }
-	
 	typealias Identifier = Id<String, PersonDescription>
+
+	static var type: String { return "people" }
 	
 	struct Attributes: JSONAPI.Attributes {
 		let name: [String]
@@ -18,12 +20,14 @@ enum PersonDescription: IdentifiedEntityDescription {
 	}
 	
 	struct Relationships: JSONAPI.Relationships {
-		let friends: ToManyRelationship<PersonDescription>
+		let friends: ToManyRelationship<Person>
 	}
 }
 
 typealias Person = Entity<PersonDescription>
 
 func tmp() {
-	let x: Person.Identifier
+	let person = Person(id: .init(rawValue: "33"), attributes: PersonDescription.Attributes(name: [], favoriteColor: "Green"), relationships: PersonDescription.Relationships(friends: .none))
+
+	print(person.pointer)
 }

README.md

@@ -137,7 +137,7 @@ This readme doesn't go into detail on the JSON API Spec, but the following JSON
 
 ### `Entity`
 
-Once you have an `EntityDescription`, you _create_, _encode_, and _decode_ `Entity`s that "fit the description". If you have a `CreatableRawIdType` (see the section on `RawIdType`s below) then you can create new `Entity<PersonDescription>`s, but even without a `CreatableRawIdType` you can decode and work with entities.
+Once you have an `EntityDescription`, you _create_, _encode_, and _decode_ `Entity`s that "fit the description". If you have a `CreatableRawIdType` (see the section on `RawIdType`s below) then you can create new `Entity<PersonDescription>`s, but even without a `CreatableRawIdType` you can encode, decode and work with entities.
 
 The `Entity` and `EntityDescription` together embody the rules and properties of a JSON API *Resource Object*.
 
@@ -215,7 +215,7 @@ The entirety of a JSON API request or response is encoded or decoded from- or to
 ```
 let decoder = JSONDecoder()
 
-let responseStructure = JSONAPIDocument<SingleResourceBody<PersonDescription>, NoIncludes, BasicJSONAPIError>.self
+let responseStructure = JSONAPIDocument<SingleResourceBody<Person>, NoIncludes, BasicJSONAPIError>.self
 
 let document = try decoder.decode(responseStructure, from: data)
 ```
@@ -230,7 +230,7 @@ The second generic type of a `JSONAPIDocument` is an `IncludeDecoder`. This type
 
 **IMPORTANT**: The number trailing "Include" in these type names does not indicate a number of included entities, it indicates a number of _types_ of included entities. `Include1` can be used to decode any number of included entities as long as all the entities are of the same _type_.
 
-To specify that we expect friends of a person to be included in the above example `JSONAPIDocument`, we would use `Include1<PersonDescription>` instead of `NoIncludes`.
+To specify that we expect friends of a person to be included in the above example `JSONAPIDocument`, we would use `Include1<Person>` instead of `NoIncludes`.
 
 #### `Error`
 

Sources/JSONAPI/Document/Includes.swift

@@ -42,14 +42,14 @@ public struct Includes<I: IncludeDecoder>: Decodable {
 
 // MARK: - Decoding
 
-func decode<EntityDescription: JSONAPI.EntityDescription>(_ type: EntityDescription.Type, from container: SingleValueDecodingContainer) throws -> Result<Entity<EntityDescription>, EncodingError> {
-	let ret: Result<Entity<EntityDescription>, EncodingError>
+func decode<Entity: JSONAPI.EntityType>(_ type: Entity.Type, from container: SingleValueDecodingContainer) throws -> Result<Entity, EncodingError> {
+	let ret: Result<Entity, EncodingError>
 	do {
-		ret = try .success(container.decode(Entity<EntityDescription>.self))
+		ret = try .success(container.decode(Entity.self))
 	} catch (let err as EncodingError) {
 		ret = .failure(err)
 	} catch (let err) {
-		ret = .failure(EncodingError.invalidValue(EntityDescription.self,
+		ret = .failure(EncodingError.invalidValue(Entity.Description.self,
 												  .init(codingPath: container.codingPath,
 														debugDescription: err.localizedDescription,
 														underlyingError: err)))
@@ -69,13 +69,13 @@ public typealias NoIncludes = Include0
 
 // MARK: - 1 include
 public protocol _Include1: _Include0 {
-	associatedtype A: EntityDescription
-	var a: Entity<A>? { get }
+	associatedtype A: EntityType
+	var a: A? { get }
 }
-public enum Include1<A: EntityDescription>: _Include1 {
-	case a(Entity<A>)
+public enum Include1<A: EntityType>: _Include1 {
+	case a(A)
 	
-	public var a: Entity<A>? {
+	public var a: A? {
 		guard case let .a(ret) = self else { return nil }
 		return ret
 	}
@@ -83,35 +83,31 @@ public enum Include1<A: EntityDescription>: _Include1 {
 	public init(from decoder: Decoder) throws {
 		let container = try decoder.singleValueContainer()
 		
-		self = .a(try container.decode(Entity<A>.self))
+		self = .a(try container.decode(A.self))
 	}
 }
 
 extension Includes where I: _Include1 {
-	public subscript(_ lookup: I.A.Type) -> [Entity<I.A>] {
+	public subscript(_ lookup: I.A.Type) -> [I.A] {
 		return values.compactMap { $0.a }
 	}
-	
-	public subscript(_ lookup: Entity<I.A>.Type) -> [Entity<I.A>] {
-		return values.compactMap { $0.a}
-	}
 }
 
 // MARK: - 2 includes
 public protocol _Include2: _Include1 {
-	associatedtype B: EntityDescription
-	var b: Entity<B>? { get }
+	associatedtype B: EntityType
+	var b: B? { get }
 }
-public enum Include2<A: EntityDescription, B: EntityDescription>: _Include2 {
-	case a(Entity<A>)
-	case b(Entity<B>)
+public enum Include2<A: EntityType, B: EntityType>: _Include2 {
+	case a(A)
+	case b(B)
 	
-	public var a: Entity<A>? {
+	public var a: A? {
 		guard case let .a(ret) = self else { return nil }
 		return ret
 	}
 	
-	public var b: Entity<B>? {
+	public var b: B? {
 		guard case let .b(ret) = self else { return nil }
 		return ret
 	}
@@ -136,36 +132,32 @@ public enum Include2<A: EntityDescription, B: EntityDescription>: _Include2 {
 }
 
 extension Includes where I: _Include2 {
-	public subscript(_ lookup: I.B.Type) -> [Entity<I.B>] {
+	public subscript(_ lookup: I.B.Type) -> [I.B] {
 		return values.compactMap { $0.b }
 	}
-	
-	public subscript(_ lookup: Entity<I.B>.Type) -> [Entity<I.B>] {
-		return values.compactMap { $0.b}
-	}
 }
 
 // MARK: - 3 includes
 public protocol _Include3: _Include2 {
-	associatedtype C: EntityDescription
-	var c: Entity<C>? { get }
+	associatedtype C: EntityType
+	var c: C? { get }
 }
-public enum Include3<A: EntityDescription, B: EntityDescription, C: EntityDescription>: _Include3 {
-	case a(Entity<A>)
-	case b(Entity<B>)
-	case c(Entity<C>)
+public enum Include3<A: EntityType, B: EntityType, C: EntityType>: _Include3 {
+	case a(A)
+	case b(B)
+	case c(C)
 	
-	public var a: Entity<A>? {
+	public var a: A? {
 		guard case let .a(ret) = self else { return nil }
 		return ret
 	}
 	
-	public var b: Entity<B>? {
+	public var b: B? {
 		guard case let .b(ret) = self else { return nil }
 		return ret
 	}
 	
-	public var c: Entity<C>? {
+	public var c: C? {
 		guard case let .c(ret) = self else { return nil }
 		return ret
 	}
@@ -191,42 +183,38 @@ public enum Include3<A: EntityDescription, B: EntityDescription, C: EntityDescri
 }
 
 extension Includes where I: _Include3 {
-	public subscript(_ lookup: I.C.Type) -> [Entity<I.C>] {
+	public subscript(_ lookup: I.C.Type) -> [I.C] {
 		return values.compactMap { $0.c }
 	}
-	
-	public subscript(_ lookup: Entity<I.C>.Type) -> [Entity<I.C>] {
-		return values.compactMap { $0.c}
-	}
 }
 
 // MARK: - 4 includes
 public protocol _Include4: _Include3 {
-	associatedtype D: EntityDescription
-	var d: Entity<D>? { get }
+	associatedtype D: EntityType
+	var d: D? { get }
 }
-public enum Include4<A: EntityDescription, B: EntityDescription, C: EntityDescription, D: EntityDescription>: _Include4 {
-	case a(Entity<A>)
-	case b(Entity<B>)
-	case c(Entity<C>)
-	case d(Entity<D>)
+public enum Include4<A: EntityType, B: EntityType, C: EntityType, D: EntityType>: _Include4 {
+	case a(A)
+	case b(B)
+	case c(C)
+	case d(D)
 	
-	public var a: Entity<A>? {
+	public var a: A? {
 		guard case let .a(ret) = self else { return nil }
 		return ret
 	}
 	
-	public var b: Entity<B>? {
+	public var b: B? {
 		guard case let .b(ret) = self else { return nil }
 		return ret
 	}
 	
-	public var c: Entity<C>? {
+	public var c: C? {
 		guard case let .c(ret) = self else { return nil }
 		return ret
 	}
 	
-	public var d: Entity<D>? {
+	public var d: D? {
 		guard case let .d(ret) = self else { return nil }
 		return ret
 	}
@@ -253,48 +241,44 @@ public enum Include4<A: EntityDescription, B: EntityDescription, C: EntityDescri
 }
 
 extension Includes where I: _Include4 {
-	public subscript(_ lookup: I.D.Type) -> [Entity<I.D>] {
+	public subscript(_ lookup: I.D.Type) -> [I.D] {
 		return values.compactMap { $0.d }
 	}
-	
-	public subscript(_ lookup: Entity<I.D>.Type) -> [Entity<I.D>] {
-		return values.compactMap { $0.d}
-	}
 }
 
 // MARK: - 5 includes
 public protocol _Include5: _Include4 {
-	associatedtype E: EntityDescription
-	var e: Entity<E>? { get }
+	associatedtype E: EntityType
+	var e: E? { get }
 }
-public enum Include5<A: EntityDescription, B: EntityDescription, C: EntityDescription, D: EntityDescription, E: EntityDescription>: _Include5 {
-	case a(Entity<A>)
-	case b(Entity<B>)
-	case c(Entity<C>)
-	case d(Entity<D>)
-	case e(Entity<E>)
+public enum Include5<A: EntityType, B: EntityType, C: EntityType, D: EntityType, E: EntityType>: _Include5 {
+	case a(A)
+	case b(B)
+	case c(C)
+	case d(D)
+	case e(E)
 	
-	public var a: Entity<A>? {
+	public var a: A? {
 		guard case let .a(ret) = self else { return nil }
 		return ret
 	}
 	
-	public var b: Entity<B>? {
+	public var b: B? {
 		guard case let .b(ret) = self else { return nil }
 		return ret
 	}
 	
-	public var c: Entity<C>? {
+	public var c: C? {
 		guard case let .c(ret) = self else { return nil }
 		return ret
 	}
 	
-	public var d: Entity<D>? {
+	public var d: D? {
 		guard case let .d(ret) = self else { return nil }
 		return ret
 	}
 	
-	public var e: Entity<E>? {
+	public var e: E? {
 		guard case let .e(ret) = self else { return nil }
 		return ret
 	}
@@ -322,54 +306,50 @@ public enum Include5<A: EntityDescription, B: EntityDescription, C: EntityDescri
 }
 
 extension Includes where I: _Include5 {
-	public subscript(_ lookup: I.E.Type) -> [Entity<I.E>] {
+	public subscript(_ lookup: I.E.Type) -> [I.E] {
 		return values.compactMap { $0.e }
 	}
-	
-	public subscript(_ lookup: Entity<I.E>.Type) -> [Entity<I.E>] {
-		return values.compactMap { $0.e}
-	}
 }
 
 // MARK: - 6 includes
 public protocol _Include6: _Include5 {
-	associatedtype F: EntityDescription
-	var f: Entity<F>? { get }
+	associatedtype F: EntityType
+	var f: F? { get }
 }
-public enum Include6<A: EntityDescription, B: EntityDescription, C: EntityDescription, D: EntityDescription, E: EntityDescription, F: EntityDescription>: _Include6 {
-	case a(Entity<A>)
-	case b(Entity<B>)
-	case c(Entity<C>)
-	case d(Entity<D>)
-	case e(Entity<E>)
-	case f(Entity<F>)
+public enum Include6<A: EntityType, B: EntityType, C: EntityType, D: EntityType, E: EntityType, F: EntityType>: _Include6 {
+	case a(A)
+	case b(B)
+	case c(C)
+	case d(D)
+	case e(E)
+	case f(F)
 	
-	public var a: Entity<A>? {
+	public var a: A? {
 		guard case let .a(ret) = self else { return nil }
 		return ret
 	}
 	
-	public var b: Entity<B>? {
+	public var b: B? {
 		guard case let .b(ret) = self else { return nil }
 		return ret
 	}
 	
-	public var c: Entity<C>? {
+	public var c: C? {
 		guard case let .c(ret) = self else { return nil }
 		return ret
 	}
 	
-	public var d: Entity<D>? {
+	public var d: D? {
 		guard case let .d(ret) = self else { return nil }
 		return ret
 	}
 	
-	public var e: Entity<E>? {
+	public var e: E? {
 		guard case let .e(ret) = self else { return nil }
 		return ret
 	}
 	
-	public var f: Entity<F>? {
+	public var f: F? {
 		guard case let .f(ret) = self else { return nil }
 		return ret
 	}
@@ -398,11 +378,7 @@ public enum Include6<A: EntityDescription, B: EntityDescription, C: EntityDescri
 }
 
 extension Includes where I: _Include6 {
-	public subscript(_ lookup: I.F.Type) -> [Entity<I.F>] {
+	public subscript(_ lookup: I.F.Type) -> [I.F] {
 		return values.compactMap { $0.f }
 	}
-	
-	public subscript(_ lookup: Entity<I.F>.Type) -> [Entity<I.F>] {
-		return values.compactMap { $0.f}
-	}
 }

Sources/JSONAPI/Document/ResourceBody.swift

@@ -8,28 +8,28 @@
 public protocol ResourceBody: Decodable {
 }
 
-public struct SingleResourceBody<EntityDescription: JSONAPI.EntityDescription>: ResourceBody {
-	public let value: Entity<EntityDescription>?
+public struct SingleResourceBody<Entity: JSONAPI.EntityType>: ResourceBody {
+	public let value: Entity?
 }
 
-public struct ManyResourceBody<EntityDescription: JSONAPI.EntityDescription>: ResourceBody {
-	public let values: [Entity<EntityDescription>]
+public struct ManyResourceBody<Entity: JSONAPI.EntityType>: ResourceBody {
+	public let values: [Entity]
 }
 
 // MARK: Decodable
 extension SingleResourceBody {
 	public init(from decoder: Decoder) throws {
 		let container = try decoder.singleValueContainer()
-		value = try container.decode(Entity<EntityDescription>.self)
+		value = try container.decode(Entity.self)
 	}
 }
 
 extension ManyResourceBody {
 	public init(from decoder: Decoder) throws {
 		var container = try decoder.unkeyedContainer()
-		var valueAggregator = [Entity<EntityDescription>]()
+		var valueAggregator = [Entity]()
 		while !container.isAtEnd {
-			valueAggregator.append(try container.decode(Entity<EntityDescription>.self))
+			valueAggregator.append(try container.decode(Entity.self))
 		}
 		values = valueAggregator
 	}

Sources/JSONAPI/Resource/Entity.swift

@@ -51,15 +51,23 @@ public protocol IdentifiedEntityDescription: EntityDescription where Identifier:
 /// new `Entity`.
 public protocol UnidentifiedEntityDescription: EntityDescription where Identifier == Unidentified {}
 
+/// EntityType is the protocol that Entity conforms to. This
+/// protocol lets other types accept any Entity as a generic
+/// specialization.
+public protocol EntityType: Codable, Equatable {
+	associatedtype Description: EntityDescription
+	associatedtype Identifier: Equatable & Codable
+}
+
 /// An `Entity` is a single model type that can be
 /// encoded to or decoded from a JSON API
 /// "Resource Object."
 /// See https://jsonapi.org/format/#document-resource-objects
-public struct Entity<EntityDescription: JSONAPI.EntityDescription>: Codable, Equatable {
-	public typealias Identifier = EntityDescription.Identifier
+public struct Entity<Description: JSONAPI.EntityDescription>: EntityType {
+	public typealias Identifier = Description.Identifier
 	
 	/// The JSON API compliant "type" of this `Entity`.
-	public static var type: String { return EntityDescription.type }
+	public static var type: String { return Description.type }
 	
 	/// The `Entity`'s Id. This can be of type `Unidentified` if
 	/// the entity is being created clientside and the
@@ -68,12 +76,12 @@ public struct Entity<EntityDescription: JSONAPI.EntityDescription>: Codable, Equ
 	public let id: Identifier
 	
 	/// The JSON API compliant attributes of this `Entity`.
-	public let attributes: EntityDescription.Attributes
+	public let attributes: Description.Attributes
 	
 	/// The JSON API compliant relationships of this `Entity`.
-	public let relationships: EntityDescription.Relationships
+	public let relationships: Description.Relationships
 	
-	public init(id: EntityDescription.Identifier, attributes: EntityDescription.Attributes, relationships: EntityDescription.Relationships) {
+	public init(id: Description.Identifier, attributes: Description.Attributes, relationships: Description.Relationships) {
 		self.id = id
 		self.attributes = attributes
 		self.relationships = relationships
@@ -81,52 +89,52 @@ public struct Entity<EntityDescription: JSONAPI.EntityDescription>: Codable, Equ
 }
 
 // MARK: Convenience initializers
-extension Entity where EntityDescription.Identifier: CreatableIdType {
-	public init(attributes: EntityDescription.Attributes, relationships: EntityDescription.Relationships) {
-		self.id = EntityDescription.Identifier()
+extension Entity where Description.Identifier: CreatableIdType {
+	public init(attributes: Description.Attributes, relationships: Description.Relationships) {
+		self.id = Description.Identifier()
 		self.attributes = attributes
 		self.relationships = relationships
 	}
 }
 
-extension Entity where EntityDescription.Attributes == NoAttributes {
-	public init(id: EntityDescription.Identifier, relationships: EntityDescription.Relationships) {
+extension Entity where Description.Attributes == NoAttributes {
+	public init(id: Description.Identifier, relationships: Description.Relationships) {
 		self.init(id: id, attributes: NoAttributes(), relationships: relationships)
 	}
 }
 
-extension Entity where EntityDescription.Attributes == NoAttributes, EntityDescription.Identifier: CreatableIdType {
-	public init(relationships: EntityDescription.Relationships) {
+extension Entity where Description.Attributes == NoAttributes, Description.Identifier: CreatableIdType {
+	public init(relationships: Description.Relationships) {
 		self.init(attributes: NoAttributes(), relationships: relationships)
 	}
 }
 
-extension Entity where EntityDescription.Relationships == NoRelatives {
-	public init(id: EntityDescription.Identifier, attributes: EntityDescription.Attributes) {
+extension Entity where Description.Relationships == NoRelatives {
+	public init(id: Description.Identifier, attributes: Description.Attributes) {
 		self.init(id: id, attributes: attributes, relationships: NoRelatives())
 	}
 }
 
-extension Entity where EntityDescription.Relationships == NoRelatives, EntityDescription.Identifier: CreatableIdType {
-	public init(attributes: EntityDescription.Attributes) {
+extension Entity where Description.Relationships == NoRelatives, Description.Identifier: CreatableIdType {
+	public init(attributes: Description.Attributes) {
 		self.init(attributes: attributes, relationships: NoRelatives())
 	}
 }
 
-extension Entity where EntityDescription.Attributes == NoAttributes, EntityDescription.Relationships == NoRelatives {
-	public init(id: EntityDescription.Identifier) {
+extension Entity where Description.Attributes == NoAttributes, Description.Relationships == NoRelatives {
+	public init(id: Description.Identifier) {
 		self.init(id: id, attributes: NoAttributes(), relationships: NoRelatives())
 	}
 }
 
-extension Entity where EntityDescription.Attributes == NoAttributes, EntityDescription.Relationships == NoRelatives, EntityDescription.Identifier: CreatableIdType {
+extension Entity where Description.Attributes == NoAttributes, Description.Relationships == NoRelatives, Description.Identifier: CreatableIdType {
 	public init() {
 		self.init(attributes: NoAttributes(), relationships: NoRelatives())
 	}
 }
 
 // MARK: Pointer for Relationships use.
-public extension Entity where EntityDescription.Identifier: IdType {
+public extension Entity where Description.Identifier: IdType {
 	/// Get a pointer to this entity that can be used as a
 	/// relationship to another entity.
 	public var pointer: ToOneRelationship<Entity> {
@@ -139,21 +147,21 @@ public extension Entity {
 	/// Access the attribute at the given keypath. This just
 	/// allows you to write `entity[\.propertyName]` instead
 	/// of `entity.relationships.propertyName`.
-	subscript<T, TFRM: Transformer>(_ path: KeyPath<EntityDescription.Attributes, TransformAttribute<T, TFRM>>) -> TFRM.To {
+	subscript<T, TFRM: Transformer>(_ path: KeyPath<Description.Attributes, TransformAttribute<T, TFRM>>) -> TFRM.To {
 		return attributes[keyPath: path].value
 	}
 	
 	/// Access the attribute at the given keypath. This just
 	/// allows you to write `entity[\.propertyName]` instead
 	/// of `entity.relationships.propertyName`.
-	subscript<T, TFRM: Transformer>(_ path: KeyPath<EntityDescription.Attributes, TransformAttribute<T, TFRM>?>) -> TFRM.To? {
+	subscript<T, TFRM: Transformer>(_ path: KeyPath<Description.Attributes, TransformAttribute<T, TFRM>?>) -> TFRM.To? {
 		return attributes[keyPath: path]?.value
 	}
 	
 	/// Access the attribute at the given keypath. This just
 	/// allows you to write `entity[\.propertyName]` instead
 	/// of `entity.relationships.propertyName`.
-	subscript<T, TFRM: Transformer, U>(_ path: KeyPath<EntityDescription.Attributes, TransformAttribute<T, TFRM>?>) -> U? where TFRM.To == U? {
+	subscript<T, TFRM: Transformer, U>(_ path: KeyPath<Description.Attributes, TransformAttribute<T, TFRM>?>) -> U? where TFRM.To == U? {
 		return attributes[keyPath: path].flatMap { $0.value }
 	}
 }
@@ -163,14 +171,14 @@ public extension Entity {
 	/// Access to an Id of a `ToOneRelationship`.
 	/// This allows you to write `entity ~> \.other` instead
 	/// of `entity.relationships.other.id`.
-	public static func ~><OtherEntity: OptionalRelatable>(entity: Entity, path: KeyPath<EntityDescription.Relationships, ToOneRelationship<OtherEntity>>) -> OtherEntity.Identifier {
+	public static func ~><OtherEntity: OptionalRelatable>(entity: Entity, path: KeyPath<Description.Relationships, ToOneRelationship<OtherEntity>>) -> OtherEntity.Identifier {
 		return entity.relationships[keyPath: path].id
 	}
 
 	/// Access to all Ids of a `ToManyRelationship`.
 	/// This allows you to write `entity ~> \.others` instead
 	/// of `entity.relationships.others.ids`.
-	public static func ~><OtherEntity: Relatable>(entity: Entity, path: KeyPath<EntityDescription.Relationships, ToManyRelationship<OtherEntity>>) -> [OtherEntity.Identifier] {
+	public static func ~><OtherEntity: Relatable>(entity: Entity, path: KeyPath<Description.Relationships, ToManyRelationship<OtherEntity>>) -> [OtherEntity.Identifier] {
 		return entity.relationships[keyPath: path].ids
 	}
 }
@@ -191,15 +199,15 @@ public extension Entity {
 		
 		try container.encode(Entity.type, forKey: .type)
 		
-		if EntityDescription.Identifier.self != Unidentified.self {
+		if Description.Identifier.self != Unidentified.self {
 			try container.encode(id, forKey: .id)
 		}
 		
-		if EntityDescription.Attributes.self != NoAttributes.self {
+		if Description.Attributes.self != NoAttributes.self {
 			try container.encode(attributes, forKey: .attributes)
 		}
 		
-		if EntityDescription.Relationships.self != NoRelatives.self {
+		if Description.Relationships.self != NoRelatives.self {
 			try container.encode(relationships, forKey: .relationships)
 		}
 	}
@@ -211,13 +219,13 @@ public extension Entity {
 		let type = try container.decode(String.self, forKey: .type)
 		
 		guard Entity.type == type else {
-			throw JSONAPIEncodingError.typeMismatch(expected: EntityDescription.type, found: type)
+			throw JSONAPIEncodingError.typeMismatch(expected: Description.type, found: type)
 		}
 		
-		id = try (Unidentified() as? EntityDescription.Identifier) ?? container.decode(EntityDescription.Identifier.self, forKey: .id)
+		id = try (Unidentified() as? Description.Identifier) ?? container.decode(Description.Identifier.self, forKey: .id)
 		
-		attributes = try (NoAttributes() as? EntityDescription.Attributes) ?? container.decode(EntityDescription.Attributes.self, forKey: .attributes)
+		attributes = try (NoAttributes() as? Description.Attributes) ?? container.decode(Description.Attributes.self, forKey: .attributes)
 		
-		relationships = try (NoRelatives() as? EntityDescription.Relationships) ?? container.decode(EntityDescription.Relationships.self, forKey: .relationships)
+		relationships = try (NoRelatives() as? Description.Relationships) ?? container.decode(Description.Relationships.self, forKey: .relationships)
 	}
 }

Sources/JSONAPI/Resource/Id.swift

@@ -48,6 +48,7 @@ public protocol CreatableIdType: IdType {
 /// An Entity ID. These IDs can be encoded to or decoded from
 /// JSON API IDs.
 public struct Id<RawType: RawIdType, EntityDescription: JSONAPI.EntityDescription>: IdType {
+
 	public let rawValue: RawType
 	
 	public init(rawValue: RawType) {

Sources/JSONAPI/Resource/Relationship.swift

@@ -53,8 +53,8 @@ extension ToManyRelationship where Relatable.Description.Identifier == Relatable
 
 /// The OptionalRelatable protocol ONLY describes
 /// Optional<T: Relatable> types.
-public protocol OptionalRelatable {
-	associatedtype Description: EntityDescription where Description.Identifier: IdType
+public protocol OptionalRelatable: Codable, Equatable where Description.Identifier: IdType {
+	associatedtype Description: EntityDescription
 	associatedtype Identifier: Equatable & Codable
 }
 
@@ -62,9 +62,7 @@ public protocol OptionalRelatable {
 /// has an EntityDescription
 public protocol Relatable: OptionalRelatable {}
 
-extension Entity: Relatable, OptionalRelatable where EntityDescription.Identifier: IdType {
-	public typealias Description = EntityDescription
-}
+extension Entity: Relatable, OptionalRelatable where Description.Identifier: IdType {}
 
 extension Optional: OptionalRelatable where Wrapped: Relatable {
 	public typealias Description = Wrapped.Description

Tests/JSONAPITests/Document/DocumentTests.swift

@@ -11,7 +11,7 @@ import JSONAPI
 class DocumentTests: XCTestCase {
 
 	func test_singleDocumentNoIncludes() {
-		let document = try? JSONDecoder().decode(JSONAPIDocument<SingleResourceBody<ArticleType>, Include0, BasicJSONAPIError>.self, from: single_document_no_includes)
+		let document = try? JSONDecoder().decode(JSONAPIDocument<SingleResourceBody<Article>, Include0, BasicJSONAPIError>.self, from: single_document_no_includes)
 		
 		XCTAssertNotNil(document)
 
@@ -24,7 +24,7 @@ class DocumentTests: XCTestCase {
 	}
 	
 	func test_singleDocumentSomeIncludes() {
-		let document = try? JSONDecoder().decode(JSONAPIDocument<SingleResourceBody<ArticleType>, Include1<AuthorType>, BasicJSONAPIError>.self, from: single_document_some_includes)
+		let document = try? JSONDecoder().decode(JSONAPIDocument<SingleResourceBody<Article>, Include1<Author>, BasicJSONAPIError>.self, from: single_document_some_includes)
 		
 		XCTAssertNotNil(document)
 
@@ -39,7 +39,7 @@ class DocumentTests: XCTestCase {
 	}
 	
 	func test_manyDocumentNoIncludes() {
-		let document = try? JSONDecoder().decode(JSONAPIDocument<ManyResourceBody<ArticleType>, Include0, BasicJSONAPIError>.self, from: many_document_no_includes)
+		let document = try? JSONDecoder().decode(JSONAPIDocument<ManyResourceBody<Article>, Include0, BasicJSONAPIError>.self, from: many_document_no_includes)
 		
 		XCTAssertNotNil(document)
 		
@@ -55,7 +55,7 @@ class DocumentTests: XCTestCase {
 	}
 	
 	func test_manyDocumentSomeIncludes() {
-		let document = try? JSONDecoder().decode(JSONAPIDocument<ManyResourceBody<ArticleType>, Include1<AuthorType>, BasicJSONAPIError>.self, from: many_document_some_includes)
+		let document = try? JSONDecoder().decode(JSONAPIDocument<ManyResourceBody<Article>, Include1<Author>, BasicJSONAPIError>.self, from: many_document_some_includes)
 		
 		XCTAssertNotNil(document)
 		

Tests/JSONAPITests/Entity/EntityTests.swift

@@ -207,6 +207,26 @@ extension EntityTests {
 	}
 }
 
+// MARK: Relationships of same type as root entity
+
+extension EntityTests {
+	func test_RleationshipsOfSameType() {
+		let entity = try? JSONDecoder().decode(TestEntity10.self, from: entity_self_ref_relationship)
+
+		XCTAssertNotNil(entity)
+
+		guard let e = entity else { return }
+
+		XCTAssertEqual((e ~> \.selfRef).rawValue, "1")
+	}
+}
+
+// MARK: Unidentified
+
+extension EntityTests {
+
+}
+
 // MARK: Test Types
 extension EntityTests {
 
@@ -349,6 +369,30 @@ extension EntityTests {
 
 	typealias TestEntity9 = Entity<TestEntityType9>
 
+	enum TestEntityType10: EntityDescription {
+		public static var type: String { return "tenth_test_entities" }
+
+		typealias Identifier = Id<String, TestEntityType10>
+
+		typealias Attributes = NoAttributes
+
+		public struct Relationships: JSONAPI.Relationships {
+			let selfRef: ToOneRelationship<TestEntity10>
+			let selfRefs: ToManyRelationship<TestEntity10>
+		}
+	}
+
+	typealias TestEntity10 = Entity<TestEntityType10>
+
+	enum UnidentifiedTestEntityType: UnidentifiedEntityDescription {
+		public static var type: String { return "unidentified_test_entities" }
+
+		typealias Attributes = NoAttributes
+		typealias Relationships = NoRelatives
+	}
+
+	typealias UnidentifiedTestEntity = Entity<UnidentifiedTestEntityType>
+
 	enum IntToString: Transformer {
 		public static func transform(_ from: Int) -> String {
 			return String(from)
@@ -374,13 +418,13 @@ extension EntityTests {
 	}
 }
 
-extension Entity where EntityDescription == EntityTests.TestEntityType2 {
+extension Entity where Description == EntityTests.TestEntityType2 {
 	init(other: ToOneRelationship<EntityTests.TestEntity1>) {
 		self.init(relationships: .init(other: other))
 	}
 }
 
-extension Entity where EntityDescription == EntityTests.TestEntityType3 {
+extension Entity where Description == EntityTests.TestEntityType3 {
 	init(others: ToManyRelationship<EntityTests.TestEntity1>) {
 		self.init(relationships: .init(others: others))
 	}

Tests/JSONAPITests/Entity/stubs/EntityStubs.swift

@@ -189,3 +189,19 @@ let entity_nulled_relationship = """
 	}
 }
 """.data(using: .utf8)!
+
+let entity_self_ref_relationship = """
+{
+	"id": "1",
+	"type": "tenth_test_entities",
+	"relationships": {
+		"selfRefs": { "data": [] },
+		"selfRef": {
+			"data": {
+				"id": "1",
+				"type": "tenth_test_entities"
+			}
+		}
+	}
+}
+""".data(using: .utf8)!

Tests/JSONAPITests/Includes/IncludeTests.swift

@@ -19,7 +19,7 @@ class IncludedTests: XCTestCase {
 	}
 	
 	func test_OneInclude() {
-		let maybeIncludes = try? decoder.decode(Includes<Include1<TestEntityType>>.self, from: one_include)
+		let maybeIncludes = try? decoder.decode(Includes<Include1<TestEntity>>.self, from: one_include)
 		
 		XCTAssertNotNil(maybeIncludes)
 
@@ -31,7 +31,7 @@ class IncludedTests: XCTestCase {
 	}
 	
 	func test_TwoSameIncludes() {
-		let maybeIncludes = try? decoder.decode(Includes<Include1<TestEntityType>>.self, from: two_same_type_includes)
+		let maybeIncludes = try? decoder.decode(Includes<Include1<TestEntity>>.self, from: two_same_type_includes)
 		
 		XCTAssertNotNil(maybeIncludes)
 		
@@ -43,7 +43,7 @@ class IncludedTests: XCTestCase {
 	}
 	
 	func test_TwoDifferentIncludes() {
-		let maybeIncludes = try? decoder.decode(Includes<Include2<TestEntityType, TestEntityType2>>.self, from: two_different_type_includes)
+		let maybeIncludes = try? decoder.decode(Includes<Include2<TestEntity, TestEntity2>>.self, from: two_different_type_includes)
 		
 		XCTAssertNotNil(maybeIncludes)
 
@@ -56,7 +56,7 @@ class IncludedTests: XCTestCase {
 	}
 	
 	func test_ThreeDifferentIncludes() {
-		let maybeIncludes = try? decoder.decode(Includes<Include3<TestEntityType, TestEntityType2, TestEntityType4>>.self, from: three_different_type_includes)
+		let maybeIncludes = try? decoder.decode(Includes<Include3<TestEntity, TestEntity2, TestEntity4>>.self, from: three_different_type_includes)
 		
 		XCTAssertNotNil(maybeIncludes)
 
@@ -70,7 +70,7 @@ class IncludedTests: XCTestCase {
 	}
 	
 	func test_FourDifferentIncludes() {
-		let maybeIncludes = try? decoder.decode(Includes<Include4<TestEntityType, TestEntityType2, TestEntityType4, TestEntityType6>>.self, from: four_different_type_includes)
+		let maybeIncludes = try? decoder.decode(Includes<Include4<TestEntity, TestEntity2, TestEntity4, TestEntity6>>.self, from: four_different_type_includes)
 		
 		XCTAssertNotNil(maybeIncludes)
 		
@@ -85,7 +85,7 @@ class IncludedTests: XCTestCase {
 	}
 	
 	func test_FiveDifferentIncludes() {
-		let maybeIncludes = try? decoder.decode(Includes<Include5<TestEntityType, TestEntityType2, TestEntityType3, TestEntityType4, TestEntityType6>>.self, from: five_different_type_includes)
+		let maybeIncludes = try? decoder.decode(Includes<Include5<TestEntity, TestEntity2, TestEntity3, TestEntity4, TestEntity6>>.self, from: five_different_type_includes)
 		
 		XCTAssertNotNil(maybeIncludes)
 		
@@ -101,7 +101,7 @@ class IncludedTests: XCTestCase {
 	}
 	
 	func test_SixDifferentIncludes() {
-		let maybeIncludes = try? decoder.decode(Includes<Include6<TestEntityType, TestEntityType2, TestEntityType3, TestEntityType4, TestEntityType5, TestEntityType6>>.self, from: six_different_type_includes)
+		let maybeIncludes = try? decoder.decode(Includes<Include6<TestEntity, TestEntity2, TestEntity3, TestEntity4, TestEntity5, TestEntity6>>.self, from: six_different_type_includes)
 		
 		XCTAssertNotNil(maybeIncludes)
 		

Tests/JSONAPITests/ResourceBody/ResourceBodyTests.swift

@@ -11,7 +11,7 @@ import JSONAPI
 class ResourceBodyTests: XCTestCase {
 
 	func test_singleResourceBody() {
-		let body = try? JSONDecoder().decode(SingleResourceBody<ArticleType>.self, from: single_resource_body)
+		let body = try? JSONDecoder().decode(SingleResourceBody<Article>.self, from: single_resource_body)
 		
 		XCTAssertNotNil(body)
 
@@ -22,7 +22,7 @@ class ResourceBodyTests: XCTestCase {
 	}
 	
 	func test_manyResourceBody() {
-		let body = try? JSONDecoder().decode(ManyResourceBody<ArticleType>.self, from: many_resource_body)
+		let body = try? JSONDecoder().decode(ManyResourceBody<Article>.self, from: many_resource_body)
 		
 		XCTAssertNotNil(body)