Removed StringKeyPaths

Since `KeyPath`s have now a description, it's unneeded to use `NSExpression`, and it's possible to directly use key path to computed properties.

Author: ABridoux

Sources/SafeFetching/Extensions/KeyPath+Extensions.swift

@@ -7,9 +7,10 @@ import Foundation
 
 extension KeyPath where Root: NSObject {
 
-    /// Name of the property pointed at
-    ///
-    /// - important: Will exit the program if the property is a computed one. The language allows
-    /// to use a `KeyPath` with a computed property, but the  'Foundation' key paths will fail in that case.
-    var label: String { NSExpression(forKeyPath: self).keyPath }
+    /// Name of the property pointed at.
+    var label: Substring {
+        let description = String(describing: self)
+        let prefixToDrop = "\\\(Root.self)."
+        return description.dropFirst(prefixToDrop.count)
+    }
 }

Sources/SafeFetching/Predicate/DatabaseValue.swift

@@ -6,11 +6,15 @@
 import Foundation
 import CoreData
 
+// MARK: - DatabaseValueIdentification
+
 /// Stub type with internal init to ensure no conformance to ``DatabaseValue`` can be added outside of the package
 public struct DatabaseValueIdentification {
     init() {}
 }
 
+// MARK: - DatabaseValue
+
 /// A type that can be used for an attribute in a predicate when fetching a CoreData store
 ///
 /// Used to constraint some fetch functions to use only a valid storable type
@@ -19,7 +23,7 @@ public protocol DatabaseValue {
     static var identification: DatabaseValueIdentification { get }
 }
 
-// MARK: Field
+// MARK: - Field
 
 extension String: DatabaseValue {
     public static let identification = DatabaseValueIdentification()
@@ -69,7 +73,13 @@ extension URL: DatabaseValue {
     public static let identification = DatabaseValueIdentification()
 }
 
-// MARK:  Relationship
+// MARK: - RawRepresentable
+
+extension RawRepresentable where RawValue: DatabaseValue {
+    public static var identification: DatabaseValueIdentification { DatabaseValueIdentification() }
+}
+
+// MARK: - Relationship
 
 extension NSManagedObject: DatabaseValue {
     public static let identification = DatabaseValueIdentification()
@@ -89,7 +99,7 @@ extension NSOrderedSet: DatabaseValue {
     public static let identification = DatabaseValueIdentification()
 }
 
-// MARK: Optional
+// MARK: - Optional
 
 extension Optional: DatabaseValue where Wrapped: DatabaseValue {
     public static var identification: DatabaseValueIdentification {

Sources/SafeFetching/Predicate/Declarations/BooleanStringKeyPathPredicate+Comparison.swift

@@ -3,38 +3,38 @@
 // Copyright © 2021-present Alexis Bridoux.
 // MIT license, see LICENSE file for details
 
-public extension Builders.StringKeyPathPredicateRightValue where Value: OptionSet, Value.RawValue: BinaryInteger, Value: DatabaseTestValue {
+public extension Builders.KeyPathPredicateRightValue where Value: OptionSet, Value.RawValue: BinaryInteger, Value: DatabaseTestValue {
 
     /// - important: Should be used only with options set types that are converted from/to a primitive value
-    static func intersects(_ value: Value) -> Builders.StringKeyPathPredicateRightValue<Entity, Value, Value> {
-        .init { keyPathString in
-            .init(keyPathString: keyPathString.key) { "\($0) & \(value.testValue) == \(value.testValue)" }
+    static func intersects(_ value: Value) -> Builders.KeyPathPredicateRightValue<Entity, Value, Value> {
+        .init { keyPath in
+                .init(keyPathString: keyPath.label) { "\($0) & \(value.testValue) == \(value.testValue)" }
         }
     }
 
     /// - important: Should be used only with options set types that are converted from/to a primitive value
-    static func doesNotIntersect(_ value: Value) -> Builders.StringKeyPathPredicateRightValue<Entity, Value, Value> {
-        .init { keyPathString in
-            .init(keyPathString: keyPathString.key) { "\($0) & \(value.testValue) != \(value.testValue)" }
+    static func doesNotIntersect(_ value: Value) -> Builders.KeyPathPredicateRightValue<Entity, Value, Value> {
+        .init { keyPath in
+            .init(keyPathString: keyPath.label) { "\($0) & \(value.testValue) != \(value.testValue)" }
         }
     }
 }
 
-public extension Builders.StringKeyPathPredicateRightValue {
+public extension Builders.KeyPathPredicateRightValue {
 
     /// - important: Should be used only with options set types that are converted from/to a primitive value
-    static func intersects<W: OptionSet & DatabaseTestValue>(_ value: W) -> Builders.StringKeyPathPredicateRightValue<Entity, Value, Value>
+    static func intersects<W: OptionSet & DatabaseTestValue>(_ value: W) -> Builders.KeyPathPredicateRightValue<Entity, Value, Value>
     where Value == W?, W.RawValue: BinaryInteger {
-        .init { keyPathString in
-            .init(keyPathString: keyPathString.key) { "\($0) & \(value.testValue) == \(value.testValue)" }
+        .init { keyPath in
+            .init(keyPathString: keyPath.label) { "\($0) & \(value.testValue) == \(value.testValue)" }
         }
     }
 
     /// - important: Should be used only with options set types that are converted from/to a primitive value
-    static func doesNotIntersect<W: OptionSet & DatabaseTestValue>(_ value: W) -> Builders.StringKeyPathPredicateRightValue<Entity, Value, Value>
+    static func doesNotIntersect<W: OptionSet & DatabaseTestValue>(_ value: W) -> Builders.KeyPathPredicateRightValue<Entity, Value, Value>
     where Value == W?, W.RawValue: BinaryInteger {
-        .init { keyPathString in
-            .init(keyPathString: keyPathString.key) { "\($0) & \(value.testValue) != \(value.testValue)" }
+        .init { keyPath in
+            .init(keyPathString: keyPath.label) { "\($0) & \(value.testValue) != \(value.testValue)" }
         }
     }
 }

Sources/SafeFetching/Predicate/Declarations/StringKeyPredicateRightValue+DatabaseValue.swift

@@ -102,51 +102,3 @@ public func || <E: NSManagedObject>(
         rightPredicate: .init(keyPath: rhs)
     )
 }
-
-// MARK: - StringKeyPath <-> Predicate
-
-public func && <E: NSManagedObject>(
-    lhs: StringKeyPath<E, Bool>,
-    rhs: Builders.Predicate<E>
-) -> Builders.CompoundPredicate<E> {
-    Builders.CompoundPredicate(
-        joinOperator: .and,
-        leftPredicate: .init(keyPathString: lhs.key),
-        rightPredicate: rhs
-    )
-}
-
-public func || <E: NSManagedObject>(
-    lhs: StringKeyPath<E, Bool>,
-    rhs: Builders.Predicate<E>
-) -> Builders.CompoundPredicate<E> {
-    Builders.CompoundPredicate(
-        joinOperator: .or,
-        leftPredicate: .init(keyPathString: lhs.key),
-        rightPredicate: rhs
-    )
-}
-
-// MARK: - Predicate <-> StringKeyPath
-
-public func && <E: NSManagedObject>(
-    lhs: Builders.Predicate<E>,
-    rhs: StringKeyPath<E, Bool>
-) -> Builders.CompoundPredicate<E> {
-    Builders.CompoundPredicate(
-        joinOperator: .and,
-        leftPredicate: lhs,
-        rightPredicate: .init(keyPathString: rhs.key)
-    )
-}
-
-public func || <E: NSManagedObject>(
-    lhs: Builders.Predicate<E>,
-    rhs: StringKeyPath<E, Bool>
-) -> Builders.CompoundPredicate<E> {
-    Builders.CompoundPredicate(
-        joinOperator: .or,
-        leftPredicate: lhs,
-        rightPredicate: .init(keyPathString: rhs.key)
-    )
-}

Sources/SafeFetching/Predicate/Declarations/StringKeyPredicateRightValue+OptionSet.swift

@@ -9,7 +9,7 @@ extension Builders {
 
     public class Predicate<Entity: NSManagedObject> {
 
-        public typealias Formatter = (_ keyPath: String) -> String
+        public typealias Formatter = (_ keyPath: Substring) -> String
 
         public let nsValue: NSPredicate
 
@@ -57,7 +57,7 @@ extension Builders.Predicate {
 extension Builders.Predicate {
 
     public convenience init<TestValue: DatabaseTestValue>(
-        keyPathString: String,
+        keyPathString: Substring,
         operatorString: String,
         value: TestValue,
         isInverted: Bool = false
@@ -67,7 +67,7 @@ extension Builders.Predicate {
     }
 
     public convenience init(
-        keyPathString: String,
+        keyPathString: Substring,
         isInverted: Bool = false,
         formatter: @escaping Formatter
     ) {
@@ -77,7 +77,7 @@ extension Builders.Predicate {
     }
 
     public convenience init(
-        keyPathString: String,
+        keyPathString: Substring,
         isInverted: Bool = false
     ) {
         let testValue = isInverted ? "0" : "1"

Sources/SafeFetching/Predicate/StringKeyPath.swift

@@ -74,16 +74,6 @@ public extension Builders.Request where Step == TargetStep {
         request.predicate = Builders.Predicate<Entity>(keyPath: keyPath).nsValue
         return .init(request: request)
     }
-
-    /// Pass a boolean string key path
-    ///
-    /// ### Examples
-    ///  - `.where(.isDownloaded)`
-    ///  - `.where(!.isDownloaded)`
-    func `where`(_ keyPath: StringKeyPath<Entity, Bool>) -> Builders.Request<Entity, PredicateStep, Output> {
-        request.predicate = Builders.Predicate<Entity>(keyPathString: keyPath.key).nsValue
-        return .init(request: request)
-    }
 }