Merge pull request #11 from p-x9/feature/omit-initial-value-when-type-is-optional

allow an initial value to be omitted when the type is Optional

Author: p-x9

Sources/AssociatedObjectPlugin/AssociatedObjectMacro.swift

@@ -82,8 +82,9 @@ extension AssociatedObjectMacro: AccessorMacro {
             return []
         }
 
-        // Initial value required
-        guard let defaultValue = binding.initializer?.value else {
+        let defaultValue = binding.initializer?.value
+        // Initial value required if type is optional
+        if defaultValue == nil && !type.isOptional {
             context.diagnose(AssociatedObjectMacroDiagnostic.requiresInitialValue.diagnose(at: declaration))
             return []
         }
@@ -103,7 +104,7 @@ extension AssociatedObjectMacro: AccessorMacro {
                         self,
                         &Self.__associated_\(identifier)Key
                     ) as? \(type)
-                    ?? \(defaultValue)
+                    ?? \(defaultValue ?? "nil")
                     """
                 }
             ),

Sources/AssociatedObjectPlugin/Extension/TypeSyntax+.swift

@@ -0,0 +1,23 @@
+//
+//  TypeSyntax+.swift
+//
+//
+//  Created by p-x9 on 2023/06/27.
+//  
+//
+
+import SwiftSyntax
+import SwiftSyntaxBuilder
+
+extension TypeSyntax {
+    var isOptional: Bool {
+        if let optionalType = self.as(OptionalTypeSyntax.self) {
+            return true
+        }
+        if let simpleType = self.as(SimpleTypeIdentifierSyntax.self),
+           simpleType.name.trimmed.text == "Optional" {
+            return true
+        }
+        return false
+    }
+}