[CHORE] Add support for throws clauese identifier type (#68)

Co-authored-by: Michael O’Brien <obrien.michael1@police.qld.gov.au>

Author: mobrien-ghost

Sources/SyntaxSparrow/Public/Semantics/Components/EffectsSpecifiers.swift

@@ -31,6 +31,10 @@ public struct EffectSpecifiers: Hashable, Equatable, CustomStringConvertible {
     /// Indicates whether the function can throw an error.
     public let throwsSpecifier: String?
 
+    /// The identifier type within a `throws` keyword, if any.
+    /// Indicates the specific error type the `throws` will produce. i.e `throws(SpecificErrorType)`
+    public let throwsIdentifier: String?
+
     /// The `asyncSpecifier` specifier, if any.
     /// Indicates whether the function supports structured concurrency.
     public let asyncSpecifier: String?
@@ -41,20 +45,23 @@ public struct EffectSpecifiers: Hashable, Equatable, CustomStringConvertible {
     public init(node: AccessorEffectSpecifiersSyntax) {
         self.node = node
         throwsSpecifier = node.throwsClause?.throwsSpecifier.text.trimmed
+        throwsIdentifier = node.throwsClause?.type?.as(IdentifierTypeSyntax.self)?.name.text.trimmed
         asyncSpecifier = node.asyncSpecifier?.text.trimmed
     }
 
     /// Creates a new ``SyntaxSparrow/EffectSpecifiers`` instance from an `TypeEffectSpecifiersSyntax` node.
     public init(node: TypeEffectSpecifiersSyntax) {
         self.node = node
         throwsSpecifier = node.throwsClause?.throwsSpecifier.text.trimmed
+        throwsIdentifier = node.throwsClause?.type?.as(IdentifierTypeSyntax.self)?.name.text.trimmed
         asyncSpecifier = node.asyncSpecifier?.text.trimmed
     }
 
     /// Creates a new ``SyntaxSparrow/EffectSpecifiers`` instance from an `FunctionEffectSpecifiersSyntax` node.
     public init(node: FunctionEffectSpecifiersSyntax) {
         self.node = node
         throwsSpecifier = node.throwsClause?.throwsSpecifier.text.trimmed
+        throwsIdentifier = node.throwsClause?.type?.as(IdentifierTypeSyntax.self)?.name.text.trimmed
         asyncSpecifier = node.asyncSpecifier?.text.trimmed
     }
 

Sources/SyntaxSparrow/Public/Semantics/Declarations/Function.swift

@@ -199,6 +199,16 @@ public struct Function: Declaration, SyntaxChildCollecting {
         return signature.effectSpecifiers?.throwsSpecifier != nil
     }
 
+    /// Returns the specific error type that is declared within the ``Function/Signature/effectSpecifiers`` when using the `throw` keyword.
+    ///
+    /// For example, the following would return `"SpecificErrorType"`:
+    /// ```swift
+    /// func example() throws(SpecificErrorType)
+    /// ```
+    public var throwsIdentifier: String? {
+        return signature.effectSpecifiers?.throwsIdentifier
+    }
+
     /// Returns `true` when the ``Function/Signature/effectSpecifiers`` has the `throw` keyword.
     ///
     /// For example, the following would return `true`:

Tests/SyntaxSparrowTests/Declarations/FunctionTests.swift

@@ -61,27 +61,41 @@ final class FunctionTests: XCTestCase {
         let source = #"""
         func executeOrder66() {}
         func executeOrder66() throws {}
+        func executeOrder66() throws(SpecificErrorType) {}
         func executeOrder66() async {}
         func executeOrder66() async throws {}
+        func executeOrder66() async throws(SpecificErrorType) {}
         """#
         instanceUnderTest.updateToSource(source)
         XCTAssertTrue(instanceUnderTest.isStale)
         instanceUnderTest.collectChildren()
         XCTAssertFalse(instanceUnderTest.isStale)
-        XCTAssertEqual(instanceUnderTest.functions.count, 4)
+        XCTAssertEqual(instanceUnderTest.functions.count, 6)
 
         // None
         XCTAssertFalse(instanceUnderTest.functions[0].isThrowing)
         XCTAssertFalse(instanceUnderTest.functions[0].isAsync)
+        XCTAssertNil(instanceUnderTest.functions[0].throwsIdentifier)
         // Throwing only
         XCTAssertTrue(instanceUnderTest.functions[1].isThrowing)
         XCTAssertFalse(instanceUnderTest.functions[1].isAsync)
+        XCTAssertNil(instanceUnderTest.functions[1].throwsIdentifier)
+        // Throwing only - specific error
+        XCTAssertTrue(instanceUnderTest.functions[2].isThrowing)
+        XCTAssertEqual(instanceUnderTest.functions[2].throwsIdentifier, "SpecificErrorType")
+        XCTAssertFalse(instanceUnderTest.functions[2].isAsync)
         // Async only
-        XCTAssertFalse(instanceUnderTest.functions[2].isThrowing)
-        XCTAssertTrue(instanceUnderTest.functions[2].isAsync)
-        // Both
-        XCTAssertTrue(instanceUnderTest.functions[3].isThrowing)
+        XCTAssertFalse(instanceUnderTest.functions[3].isThrowing)
         XCTAssertTrue(instanceUnderTest.functions[3].isAsync)
+        XCTAssertNil(instanceUnderTest.functions[3].throwsIdentifier)
+        // Both
+        XCTAssertTrue(instanceUnderTest.functions[4].isThrowing)
+        XCTAssertTrue(instanceUnderTest.functions[4].isAsync)
+        XCTAssertNil(instanceUnderTest.functions[4].throwsIdentifier)
+        // Both - Specific Error
+        XCTAssertTrue(instanceUnderTest.functions[5].isThrowing)
+        XCTAssertTrue(instanceUnderTest.functions[5].isAsync)
+        XCTAssertEqual(instanceUnderTest.functions[5].throwsIdentifier, "SpecificErrorType")
     }
 
     func test_function_withChildDeclarations_willResolveExpectedChildDeclarations() throws {