Improve compatibility with Embedded Swift (#58)

The change adds a conditional import excluding the JavaScriptEventLoop module that's not yet fully compatible with Embedded Swift. With the `JSObject` type from the JavaScriptKit dependency, which is also now compatible with Embedded Swift, record types are now mapped to `JSObject`. As for fields marked as optional in originating IDL, these are now correctly mapped as optional in Swift.

Author: MaxDesiatov

Sources/WebIDLToSwift/IDLBuilder.swift

@@ -3,6 +3,7 @@ import WebIDL
 
 enum IDLBuilder {
     static let basicDependencies = ["ECMAScript", "JavaScriptKit", "JavaScriptEventLoop"]
+    static let optionalDependencies = ["JavaScriptEventLoop"]
 
     static let preamble = """
     // This file was auto-generated by WebIDLToSwift. DO NOT EDIT!
@@ -42,7 +43,11 @@ enum IDLBuilder {
             dependencies.append("JavaScriptBigIntSupport")
         }
 
-        let formedPreamble = preamble + dependencies.map { "import \($0)" }.joined(separator: "\n")
+        let formedPreamble = preamble + (optionalDependencies.map { """
+        #if canImport\($0)
+            import \($0)
+        #endif
+        """ } + dependencies.map { "import \($0)" }).joined(separator: "\n")
 
         try (formedPreamble + "\n\n" + content).write(toFile: path, atomically: true, encoding: .utf8)
     }
@@ -54,6 +59,7 @@ enum IDLBuilder {
         var contents: [SwiftSource] = []
 
         var state = ScopedState.root(
+            dictionaries: merged.dictionaries,
             interfaces: merged.interfaces,
             ignored: [
                 // variadic callbacks are unsupported

Sources/WebIDLToSwift/MergeDeclarations.swift

@@ -18,6 +18,10 @@ enum DeclarationMerger {
 
     private static func enhanceMembers(_ members: [IDLNode]) -> [IDLNode] {
         members.flatMap { member -> [IDLNode] in
+            if let named = member as? IDLNamed, named.name.contains("-") {
+                return []
+            }
+
             if let operation = member as? IDLOperation,
                case .generic("Promise", _) = operation.idlType?.value
             {
@@ -223,6 +227,7 @@ enum DeclarationMerger {
                 + [Typedefs(typedefs: allTypes)]
                 + allNodes(ofType: IDLEnum.self)
                 + allNodes(ofType: IDLCallbackInterface.self),
+            dictionaries: mergedDictionaries,
             interfaces: mergedInterfaces,
             types: mergedTypes
             // unions: unions
@@ -231,6 +236,7 @@ enum DeclarationMerger {
 
     struct MergeResult {
         let declarations: [DeclarationFile]
+        let dictionaries: [String: MergedDictionary]
         let interfaces: [String: MergedInterface]
         let types: [String: IDLTypealias]
         // let unions: Set<UnionType>

Sources/WebIDLToSwift/ModuleState.swift

@@ -63,6 +63,7 @@ struct ScopedState {
     private(set) var this: SwiftSource!
     private(set) var className: SwiftSource!
     private(set) var interfaces: [String: MergedInterface]!
+    private(set) var dictionaries: [String: MergedDictionary]!
     private(set) var ignored: [String: Set<String>]!
     private(set) var types: [String: IDLTypealias]!
     private(set) var override = false
@@ -106,12 +107,14 @@ struct ScopedState {
     }
 
     static func root(
+        dictionaries: [String: MergedDictionary],
         interfaces: [String: MergedInterface],
         ignored: [String: Set<String>],
         types: [String: IDLTypealias]
     ) -> Self {
         var newState = ModuleState.current
         newState.interfaces = interfaces
+        newState.dictionaries = dictionaries
         newState.ignored = ignored
         newState.types = types
         return newState

Sources/WebIDLToSwift/UnionType+SwiftRepresentable.swift

@@ -74,7 +74,7 @@ extension UnionType: SwiftRepresentable {
     var initializers: [SwiftSource] {
         zip(sortedTypes, sortedNames).flatMap { (type, name) -> [SwiftSource] in
             let basicInitializer: [SwiftSource] = ["""
-            init(_ \(name): \(type)) {
+            public init(_ \(name): \(type)) {
                 let val: \(self.name) = .\(name)(\(name))
                 self = val
             }
@@ -162,10 +162,8 @@ extension SlimIDLType: SwiftRepresentable {
             case "FrozenArray", "ObservableArray":
                 // ???
                 return ["Element == \(args[0])"]
-            case "Promise":
+            case "Promise", "record":
                 return []
-            case "record":
-                return ["Key == \(args[0])", "Value == \(args[1])"]
             default:
                 fatalError("Unsupported generic type: \(name)")
             }
@@ -190,7 +188,7 @@ extension SlimIDLType.TypeValue: SwiftRepresentable {
             case "Promise":
                 return "JSPromise"
             case "record":
-                return "Dictionary"
+                return "JSObject"
             default:
                 fatalError("Unsupported generic type: \(name)")
             }
@@ -220,7 +218,7 @@ extension SlimIDLType.TypeValue: SwiftRepresentable {
             case "Promise":
                 return "JSPromise"
             case "record":
-                return "[\(args[0]): \(args[1])]"
+                return "JSObject"
             default:
                 fatalError("Unsupported generic type: \(name)")
             }

Sources/WebIDLToSwift/WebIDL+SwiftRepresentation.swift

@@ -88,6 +88,16 @@ extension IDLAttribute: SwiftRepresentable, Initializable {
     }
 }
 
+extension IDLDictionary.Member {
+    var isOptional: Bool {
+        !required && !idlType.nullable && !idlType.isFunction
+    }
+
+    var optionalSuffix: String {
+        isOptional ? "?" : ""
+    }
+}
+
 extension MergedDictionary: SwiftRepresentable {
     var swiftRepresentation: SwiftSource {
         """
@@ -98,7 +108,7 @@ extension MergedDictionary: SwiftRepresentable {
         """
     }
 
-    private var membersWithPropertyWrapper: [(IDLDictionary.Member, SwiftSource)] {
+    private func membersWithPropertyWrapper(_ members: [IDLDictionary.Member]) -> [(IDLDictionary.Member, SwiftSource)] {
         members.map {
             ($0, $0.idlType.propertyWrapper(readonly: false))
         }
@@ -111,7 +121,7 @@ extension MergedDictionary: SwiftRepresentable {
         return """
         public convenience init(\(sequence: params)) {
             let object = JSObject.global[\(ModuleState.source(for: "Object"))].function!.new()
-            \(lines: membersWithPropertyWrapper.map { member, wrapper in
+            \(lines: membersWithPropertyWrapper(members).map { member, wrapper in
                 if member.idlType.isFunction {
                     return """
                     \(wrapper)[\(ModuleState.source(for: member.name)), in: object] = \(member.name)
@@ -126,7 +136,7 @@ extension MergedDictionary: SwiftRepresentable {
         }
 
         public required init(unsafelyWrapping object: JSObject) {
-            \(lines: membersWithPropertyWrapper.map { member, wrapper in
+            \(lines: membersWithPropertyWrapper(members).map { member, wrapper in
                 "_\(raw: member.name) = \(wrapper)(jsObject: object, name: \(ModuleState.source(for: member.name)))"
             })
             super.init(unsafelyWrapping: object)
@@ -135,10 +145,10 @@ extension MergedDictionary: SwiftRepresentable {
     }
 
     private var swiftMembers: [SwiftSource] {
-        membersWithPropertyWrapper.map { member, wrapper in
+        self.membersWithPropertyWrapper(members).map { member, wrapper in
             """
             @\(wrapper)
-            public var \(member.name): \(member.idlType)
+            public var \(member.name): \(member.idlType)\(member.optionalSuffix)
             """
         }
     }