Merge pull request #30 from ABridoux/fetchable-value

# New FetchableValue protocol
Removed DatabaseValue and DatabaseTestValue protocol in favor of a single protocol FetchableValue to make it easier for complex types to be used in a predicate.

Also added support for NSManagedObject and NSManagedObjectID comparison and to-many relationship contains operator.

Author: ABridoux

Sources/SafeFetching/Extensions/NSPredicate+Convenience.swift

@@ -9,12 +9,29 @@ import CoreData
 
 extension NSPredicate {
 
-    /// Safely builds a predicate for a provided entity type.
+    /// Returns a `NSPredicate` built from a SafeFetching predicate.
+    /// - Parameter predicate: A predicate which will be mapped to as `NSPredicate`.
     public static func safe<Entity: Fetchable>(_ predicate: Builders.Predicate<Entity>) -> NSPredicate {
         predicate.nsValue
     }
 
-    /// Safely builds a predicate for a provided entity type.
+    /// Returns a `NSPredicate` built from a SafeFetching predicate.
+    /// - Parameters:
+    ///   - _: Entity type used to build the predicate.
+    ///   - predicate: A closure that takes an `Entity.FetchableMembers` value to return a SafeFetching predicate.
+    @_disfavoredOverload
+    public static func safe<SourceEntity: Fetchable>(
+        on _: SourceEntity.Type,
+        _ predicate: (SourceEntity.FetchableMembers) -> Builders.Predicate<SourceEntity>
+    ) -> NSPredicate {
+        let predicate = predicate(SourceEntity.fetchableMembers)
+        return predicate.nsValue
+    }
+
+    /// Returns a `NSPredicate` built from a SafeFetching predicate.
+    /// - Parameters:
+    ///   - _: Entity type used to build the predicate.
+    ///   - predicate: A closure that takes an `Entity.FetchableMembers` value to return a SafeFetching predicate.
     public static func safe<SourceEntity: Fetchable, TargetEntity: Fetchable>(
         on _: SourceEntity.Type,
         _ predicate: (SourceEntity.FetchableMembers) -> Builders.Predicate<TargetEntity>
@@ -23,7 +40,10 @@ extension NSPredicate {
         return predicate.nsValue
     }
 
-    /// Safely builds a predicate for a provided entity type.
+    /// Returns a `NSPredicate` built from a SafeFetching predicate.
+    /// - Parameters:
+    ///   - _: Entity type used to build the predicate.
+    ///   - fetchableMember: A closure that takes an `Entity.FetchableMembers` value to return a `FetchableMember` targeting a Boolean attribute of `Entity`.
     public static func safe<SourceEntity: Fetchable, TargetEntity: Fetchable>(
         on _: SourceEntity.Type,
         _ fetchableMember: (SourceEntity.FetchableMembers) -> FetchableMember<TargetEntity, Bool>

Sources/SafeFetching/Macros.swift

@@ -5,7 +5,7 @@
 
 // MARK: - FetchableManagedObject
 
-/// Add `FetchableMembers` and `fetchableMembers` to a `NSManagedObject` to make it conform to `Fetchable`.
+/// Add `FetchableMembers` and `fetchableMembers` to a `NSManagedObject` to make it conform to `Fetchable` and add `FetchableMembers`.
 @attached(member, names: arbitrary)
 @attached(extension, conformances: Fetchable)
 public macro FetchableManagedObject() = #externalMacro(module: "SafeFetchingMacros", type: "FetchableManagedObjectMacro")