Fix support for setting default flag values

Sources/OnboardingKit/OnboardingEvent.swift

@@ -20,19 +20,6 @@ public protocol OnboardingEventProtocol {
  /// - Warning: Don’t call this method yourself.
  func check()
 
- /// Attempts to set the specified flag to a default value.
- ///
- /// This method should fail silently if no default value can be inferred.
- /// - Parameter keyPath: The key path at which to set the default value.
- /// - Warning: Don’t call this method yourself.
- func setDefaultValue<Flags, Value>(at keyPath: ReferenceWritableKeyPath<Flags, Value>)
-
-}
-
-extension OnboardingEventProtocol {
-
- public func setDefaultValue<Flags, Value>(at: ReferenceWritableKeyPath<Flags, Value>) { }
-
 }
 
 /// An event that occurs when all of its constituent conditions are satisfied.
@@ -103,8 +90,10 @@ public final class OnboardingEvent<Flags, Value>: OnboardingEventProtocol where
  if let keyPath = self.keyPath {
  self.flags[keyPath: keyPath] = self.value
  }
- } else if let keyPath = self.keyPath {
- self.setDefaultValue(at: keyPath)
+ } else if let keyPath = self.keyPath as? ReferenceWritableKeyPath<Flags, Bool> {
+ self.flags[keyPath: keyPath] = false
+ } else if let keyPath = self.keyPath, let defaultValue = (Value.self as? OptionalProtocol.Type)?.none as? Value {
+ self.flags[keyPath: keyPath] = defaultValue
  }
  }
 
@@ -130,16 +119,4 @@ public extension OnboardingEvent where Value == Bool {
  self.init(flags: flags, settingFlagAt: keyPath, to: true, conditions: conditions)
  }
 
- func setDefaultValue(at keyPath: ReferenceWritableKeyPath<Flags, Bool>) {
- self.flags[keyPath: keyPath] = false
- }
-
-}
-
-public extension OnboardingEvent where Value: ExpressibleByNilLiteral {
-
- func setDefaultValue(at keyPath: ReferenceWritableKeyPath<Flags, Value>) {
- self.flags[keyPath: keyPath] = nil
- }
-
 }

Sources/OnboardingKit/OptionalProtocol.swift

@@ -0,0 +1,14 @@
+//
+// OptionalProtocol.swift
+// OnboardingKit
+//
+// Created by Gabriel Jacoby-Cooper on 12/23/21.
+//
+
+protocol OptionalProtocol {
+
+ static var none: Self { get }
+
+}
+
+extension Optional: OptionalProtocol { }