Conform to SWON coding protocols

README.md

@@ -66,8 +66,9 @@ SWON uses the amazingly written [cJSON][credits-cjson] parser (C) under the hood
 
 ### Things to do
 
+- Handle `RawRepresentable` automatically.
 - Do not suppress errors inside an optional field (silently made nil).
-- Add thorough tests add meaningful examples.
+- Add thorough tests and meaningful examples.
 - Clean up some messy code.
 
 ## License

Sources/SWON/Extensions.swift

@@ -0,0 +1,45 @@
+// SPDX-FileCopyrightText: 2026 Davide De Rosa
+//
+// SPDX-License-Identifier: MIT
+
+extension Array: SWONDecodable, SWONEncodable where Element: SWONDecodable & SWONEncodable {
+    public init(fromSWON root: swon_t) throws {
+        var list: [Element] = []
+        var array = swon_t()
+        guard swon_get_array(&array, root) == SWONResultValid else {
+            throw SWONError.required("Array")
+        }
+        let size = swon_get_array_size(array)
+        for i in 0..<size {
+            var item = swon_t()
+            let result = swon_get_array_item(&item, array, Int32(i))
+            guard result == SWONResultValid else { throw SWONError.invalid("Array") }
+            let el = try Element(fromSWON: item)
+            list.append(el)
+        }
+        self = list
+    }
+
+    public func toSWON() throws -> swon_t {
+        let list = Array(self)
+        var root = swon_t()
+        guard swon_create_array(&root) else { throw SWONError.invalid("Array") }
+        for el in list {
+            let item = try el.toSWON()
+            guard swon_array_add_item(&root, item) else {
+                throw SWONError.invalid("Array: Element")
+            }
+        }
+        return root
+    }
+}
+
+extension Set: SWONDecodable, SWONEncodable where Element: SWONDecodable & SWONEncodable {
+    public init(fromSWON root: swon_t) throws {
+        self = try Set(Array(fromSWON: root))
+    }
+
+    public func toSWON() throws -> swon_t {
+        try Array(self).toSWON()
+    }
+}

Sources/SWON/Protocols.swift

@@ -0,0 +1,11 @@
+// SPDX-FileCopyrightText: 2026 Davide De Rosa
+//
+// SPDX-License-Identifier: MIT
+
+public protocol SWONEncodable {
+    func toSWON() throws -> swon_t
+}
+
+public protocol SWONDecodable {
+    init(fromSWON root: swon_t) throws
+}

Sources/SWON/SWON.swift

@@ -10,6 +10,10 @@
             named(toSWON),
             named(toJSON)
 )
+@attached(
+    extension,
+    conformances: SWONEncodable, SWONDecodable
+)
 public macro SWON() = #externalMacro(
     module: "SWONMacros",
     type: "SWONCompoundMacro"

Sources/SWONMacros/Decoding.swift

@@ -151,7 +151,7 @@ struct SWONDecodeMacro: MemberMacro {
 //                context.diagnose(
 //                    Diagnostic(
 //                        node: Syntax(node),
-//                        message: SWONMessage(message: "Assigning \(field) of type \(type)")
+//                        message: SWONMessage(message: "Assigning \(field) of type \(type) (decoded: \(type.decodedType(context: context)))")
 //                    )
 //                )
                 assignments.append("""

Sources/SWONMacros/Macros.swift

@@ -13,7 +13,7 @@ struct SWONMacrosPlugin: CompilerPlugin {
     ]
 }
 
-public struct SWONCompoundMacro: MemberMacro {
+public struct SWONCompoundMacro: MemberMacro, ExtensionMacro {
     public static func expansion(
         of node: AttributeSyntax,
         providingMembersOf declaration: some DeclGroupSyntax,
@@ -35,4 +35,41 @@ public struct SWONCompoundMacro: MemberMacro {
         )
         return result
     }
+
+    public static func expansion(
+        of node: AttributeSyntax,
+        attachedTo declaration: some DeclGroupSyntax,
+        providingExtensionsOf type: some TypeSyntaxProtocol,
+        conformingTo protocols: [TypeSyntax],
+        in context: some MacroExpansionContext
+    ) throws -> [ExtensionDeclSyntax] {
+        // Extract the type name (struct/class/enum identifier)
+        guard let named = declaration.asProtocol(NamedDeclSyntax.self) else {
+            return []
+        }
+        let typeName = named.name.text
+
+        // Optional: avoid duplicate conformances if already declared
+        let alreadyConforms: Set<String> =
+        declaration.inheritanceClause?
+            .inheritedTypes
+            .compactMap { $0.type.as(IdentifierTypeSyntax.self)?.name.text }
+            .reduce(into: Set<String>()) { $0.insert($1) }
+        ?? []
+        let needsEncodable = !alreadyConforms.contains("SWONEncodable")
+        let needsDecodable = !alreadyConforms.contains("SWONDecodable")
+        guard needsEncodable || needsDecodable else {
+            return []
+        }
+
+        // Build the conformance list dynamically
+        var conformances: [String] = []
+        if needsEncodable { conformances.append("SWONEncodable") }
+        if needsDecodable { conformances.append("SWONDecodable") }
+        let conformanceList = conformances.joined(separator: ", ")
+        let ext = try ExtensionDeclSyntax(
+            "extension \(raw: typeName): \(raw: conformanceList) {}"
+        )
+        return [ext]
+    }
 }

Sources/SWON_C/swon.c

@@ -119,7 +119,7 @@ swon_t swon_get_map_next(swon_t src) {
 
 bool swon_create_array(swon_t *dst) {
     dst->impl = cJSON_CreateArray();
-    return dst->impl;
+    return dst->impl != NULL;
 }
 
 bool swon_array_add_item(swon_t *dst, swon_t item) {

Tests/SWONTests/ComplexStruct.swift

@@ -52,6 +52,9 @@ struct ComplexStruct: Equatable, Codable {
     let optionalStringToSubStructArray: [String: [SubStruct]]?
 
     let uint16: UInt16?
+
+    // Set
+    let someSet: Set<Color>?
 }
 
 @SWON

Tests/SWONTests/Resources/populated.json

@@ -131,5 +131,6 @@
             ]
         }]
     },
-    "uint16": 60000
+    "uint16": 60000,
+    "someSet": ["blue", "red", "green"]
 }

Tests/SWONTests/SWONTests.swift

@@ -23,13 +23,6 @@ struct SWONTests {
 
     @Test
     func encodingAssociatedEnums() throws {
-        @SWON
-        struct LocalContainer {
-            let enums: [AssociatedEnum]
-            init(enums: [AssociatedEnum]) {
-                self.enums = enums
-            }
-        }
         let sub = try SubStruct(fromJSON: """
         {
             "favoriteColor": "red",
@@ -81,7 +74,8 @@ struct SWONTests {
     "nestedColors": [
         ["green", "blue"],
         ["red", "red", "green"]
-    ]
+    ],
+    "colorSet": ["red", "green"]
 }
 """)
         print(try sut.toJSON())
@@ -116,6 +110,7 @@ struct LocalStruct {
     let another: AnotherStruct?
     let nestedStrings: [[String]]
     let nestedColors: [[Color]]
+    let colorSet: Set<Color>
 }
 
 @SWON