feat: added internally tagged enum support

Author: soumyamahunt

Sources/CodableMacroPlugin/Attributes/Codable/Codable.swift

@@ -31,7 +31,7 @@ struct Codable: Attribute {
     init?(from node: AttributeSyntax) {
         guard
             node.attributeName.as(IdentifierTypeSyntax.self)!
-                .description == Self.name
+                .name.text == Self.name
         else { return nil }
         self.node = node
     }

Sources/CodableMacroPlugin/Attributes/Codable/CodingKeys/CodingKeys.swift

@@ -31,7 +31,7 @@ struct CodingKeys: PeerAttribute {
     init?(from node: AttributeSyntax) {
         guard
             node.attributeName.as(IdentifierTypeSyntax.self)!
-                .description == Self.name
+                .name.text == Self.name
         else { return nil }
         self.node = node
     }

Sources/CodableMacroPlugin/Attributes/Codable/IgnoreCodingInitialized.swift

@@ -24,7 +24,7 @@ struct IgnoreCodingInitialized: PeerAttribute {
     init?(from node: AttributeSyntax) {
         guard
             node.attributeName.as(IdentifierTypeSyntax.self)!
-                .description == Self.name
+                .name.text == Self.name
         else { return nil }
         self.node = node
     }

Sources/CodableMacroPlugin/Attributes/CodedAs.swift

@@ -11,9 +11,18 @@ struct CodedAs: PropertyAttribute {
     let node: AttributeSyntax
 
     /// The alternate value expression provided.
-    var expr: ExprSyntax {
-        return node.arguments!
-            .as(LabeledExprListSyntax.self)!.first!.expression
+    var expr: ExprSyntax? {
+        return node.arguments?
+            .as(LabeledExprListSyntax.self)?.first?.expression
+    }
+
+    /// The type to which to be decoded/encoded.
+    ///
+    /// Used for enums with internal/adjacent tagging to decode
+    /// the identifier to this type.
+    var type: TypeSyntax? {
+        return node.attributeName.as(IdentifierTypeSyntax.self)?
+            .genericArgumentClause?.arguments.first?.argument
     }
 
     /// Creates a new instance with the provided node.
@@ -26,7 +35,7 @@ struct CodedAs: PropertyAttribute {
     init?(from node: AttributeSyntax) {
         guard
             node.attributeName.as(IdentifierTypeSyntax.self)!
-                .description == Self.name
+                .name.text == Self.name
         else { return nil }
         self.node = node
     }
@@ -36,17 +45,35 @@ struct CodedAs: PropertyAttribute {
     ///
     /// The following conditions are checked by the
     /// built diagnoser:
-    /// * Attached declaration is an enum-case declaration.
     /// * Macro usage is not duplicated for the same declaration.
-    /// * This attribute isn't used combined with `IgnoreCoding`
+    /// * If macro has zero arguments provided:
+    ///   * Attached declaration is an enum declaration.
+    ///   * This attribute must be combined with `Codable`
+    ///   and `TaggedAt` attribute.
+    ///   * This attribute mustn't be combined with `CodedBy`
+    ///   attribute.
+    /// * If macro has one argument provided:
+    ///   * Attached declaration is an enum-case declaration.
+    ///   * This attribute isn't used combined with `IgnoreCoding`
     ///   attribute.
     ///
     /// - Returns: The built diagnoser instance.
     func diagnoser() -> DiagnosticProducer {
         return AggregatedDiagnosticProducer {
-            expect(syntaxes: EnumCaseDeclSyntax.self)
             cantDuplicate()
-            cantBeCombined(with: IgnoreCoding.self)
+            `if`(
+                has(arguments: 1),
+                AggregatedDiagnosticProducer {
+                    expect(syntaxes: EnumCaseDeclSyntax.self)
+                    cantBeCombined(with: IgnoreCoding.self)
+                },
+                else: AggregatedDiagnosticProducer {
+                    expect(syntaxes: EnumDeclSyntax.self)
+                    mustBeCombined(with: Codable.self)
+                    mustBeCombined(with: TaggedAt.self)
+                    cantBeCombined(with: CodedBy.self)
+                }
+            )
         }
     }
 }

Sources/CodableMacroPlugin/Attributes/CodedBy.swift

@@ -27,7 +27,7 @@ struct CodedBy: PropertyAttribute {
     init?(from node: AttributeSyntax) {
         guard
             node.attributeName.as(IdentifierTypeSyntax.self)!
-                .description == Self.name
+                .name.text == Self.name
         else { return nil }
         self.node = node
     }
@@ -37,21 +37,36 @@ struct CodedBy: PropertyAttribute {
     ///
     /// The following conditions are checked by the
     /// built diagnoser:
-    /// * Attached declaration is a variable declaration.
-    /// * Attached declaration is not a static variable
-    ///   declaration
-    /// * Macro usage is not duplicated for the same
-    ///   declaration.
-    /// * This attribute isn't used combined with
-    ///   `IgnoreCoding` attribute.
+    /// * Macro usage is not duplicated for the same declaration.
+    /// * If attached declaration is enum declaration:
+    ///   * This attribute must be combined with `Codable`
+    ///     and `TaggedAt` attribute.
+    ///   * This attribute mustn't be combined with `CodedAs`
+    ///     attribute.
+    /// * If macro has one argument provided:
+    ///   * Attached declaration is a variable declaration.
+    ///   * Attached declaration is not a static variable
+    ///     declaration
+    ///   * This attribute isn't used combined with
+    ///     `IgnoreCoding` attribute.
     ///
     /// - Returns: The built diagnoser instance.
     func diagnoser() -> DiagnosticProducer {
         return AggregatedDiagnosticProducer {
-            expect(syntaxes: VariableDeclSyntax.self)
-            attachedToNonStaticVariable()
             cantDuplicate()
-            cantBeCombined(with: IgnoreCoding.self)
+            `if`(
+                isEnum,
+                AggregatedDiagnosticProducer {
+                    mustBeCombined(with: Codable.self)
+                    mustBeCombined(with: TaggedAt.self)
+                    cantBeCombined(with: CodedAs.self)
+                },
+                else: AggregatedDiagnosticProducer {
+                    expect(syntaxes: VariableDeclSyntax.self)
+                    attachedToNonStaticVariable()
+                    cantBeCombined(with: IgnoreCoding.self)
+                }
+            )
         }
     }
 }

Sources/CodableMacroPlugin/Attributes/Default.swift

@@ -26,7 +26,7 @@ struct Default: PropertyAttribute {
     init?(from node: AttributeSyntax) {
         guard
             node.attributeName.as(IdentifierTypeSyntax.self)!
-                .description == Self.name
+                .name.text == Self.name
         else { return nil }
         self.node = node
     }

Sources/CodableMacroPlugin/Attributes/IgnoreCoding/IgnoreCoding.swift

@@ -22,7 +22,7 @@ struct IgnoreCoding: PropertyAttribute {
     init?(from node: AttributeSyntax) {
         guard
             node.attributeName.as(IdentifierTypeSyntax.self)!
-                .description == Self.name
+                .name.text == Self.name
         else { return nil }
         self.node = node
     }

Sources/CodableMacroPlugin/Attributes/IgnoreCoding/IgnoreDecoding.swift

@@ -22,7 +22,7 @@ struct IgnoreDecoding: PropertyAttribute {
     init?(from node: AttributeSyntax) {
         guard
             node.attributeName.as(IdentifierTypeSyntax.self)!
-                .description == Self.name
+                .name.text == Self.name
         else { return nil }
         self.node = node
     }

Sources/CodableMacroPlugin/Attributes/IgnoreCoding/IgnoreEncoding.swift

@@ -22,7 +22,7 @@ struct IgnoreEncoding: PropertyAttribute {
     init?(from node: AttributeSyntax) {
         guard
             node.attributeName.as(IdentifierTypeSyntax.self)!
-                .description == Self.name
+                .name.text == Self.name
         else { return nil }
         self.node = node
     }

Sources/CodableMacroPlugin/Attributes/KeyPath/CodedAt.swift

@@ -22,7 +22,7 @@ struct CodedAt: PropertyAttribute {
     init?(from node: AttributeSyntax) {
         guard
             node.attributeName.as(IdentifierTypeSyntax.self)!
-                .description == Self.name
+                .name.text == Self.name
         else { return nil }
         self.node = node
     }