Add Swift tree-sitter language support

docs/src/content/docs/core-concepts/plugin-system.mdx

@@ -24,6 +24,7 @@ kit comes with built-in support for 12+ programming languages:
 - **Dart** (`.dart`) - Classes, functions, mixins, enums, extensions
 - **HCL/Terraform** (`.hcl`, `.tf`) - Resources, variables, modules
 - **Haskell** (`.hs`) - Module header, functions (including lambda-binds), common type-level declarations
+- **Swift** (`.swift`) - Classes, structs, enums, protocols, actors, extensions, functions
 
 Each language supports comprehensive symbol extraction including:
 - **Classes and interfaces** with inheritance relationships

src/kit/queries/swift/tags.scm

@@ -0,0 +1,42 @@
+;; tags.scm for Swift symbol extraction (tree-sitter-swift)
+
+; Function declarations
+(function_declaration
+  name: (simple_identifier) @name) @definition.function
+
+; Class declarations (keyword-differentiated from struct/enum/extension)
+(class_declaration
+  "class"
+  name: (type_identifier) @name) @definition.class
+
+; Actor declarations
+(class_declaration
+  "actor"
+  name: (type_identifier) @name) @definition.actor
+
+; Struct declarations
+(class_declaration
+  "struct"
+  name: (type_identifier) @name) @definition.struct
+
+; Enum declarations
+(class_declaration
+  "enum"
+  name: (type_identifier) @name) @definition.enum
+
+; Extension declarations (name field is user_type, not type_identifier)
+(class_declaration
+  "extension"
+  name: (user_type) @name) @definition.extension
+
+; Protocol declarations
+(protocol_declaration
+  name: (type_identifier) @name) @definition.protocol
+
+; Type alias declarations
+(typealias_declaration
+  name: (type_identifier) @name) @definition.typealias
+
+; Initializer declarations
+(init_declaration
+  "init" @name) @definition.initializer

src/kit/tree_sitter_symbol_extractor.py

@@ -34,6 +34,7 @@
     ".hxx": "cpp",
     ".zig": "zig",
     ".cs": "csharp",
+    ".swift": "swift",
 }
 
 
@@ -350,6 +351,7 @@ def reset_plugins(cls) -> None:
             ".hxx": "cpp",
             ".zig": "zig",
             ".cs": "csharp",
+            ".swift": "swift",
         }
         LANGUAGES.clear()
         LANGUAGES.update(original_languages)

tests/test_swift_symbols.py

@@ -0,0 +1,91 @@
+import pytest
+
+from kit.tree_sitter_symbol_extractor import TreeSitterSymbolExtractor
+
+SWIFT_SAMPLE = """\
+class Animal {
+    var name: String
+    init(name: String) {
+        self.name = name
+    }
+}
+
+struct Point {
+    var x: Int
+    var y: Int
+}
+
+enum Direction {
+    case north, south, east, west
+}
+
+extension Animal {
+    func speak() -> String {
+        return name
+    }
+}
+
+actor Worker {
+    func run() {}
+}
+
+protocol Drawable {
+    func draw()
+}
+
+typealias StringMap = [String: String]
+
+func greet(person: String) -> String {
+    return "Hello, \\(person)!"
+}
+"""
+
+
+def test_swift_parser_and_query_available():
+    parser = TreeSitterSymbolExtractor.get_parser(".swift")
+    query = TreeSitterSymbolExtractor.get_query(".swift")
+    if not parser or not query:
+        pytest.skip("Swift parser or query not available in this environment")
+
+    tree = parser.parse(SWIFT_SAMPLE.encode("utf-8"))
+    assert tree.root_node is not None
+
+
+def test_swift_symbols():
+    parser = TreeSitterSymbolExtractor.get_parser(".swift")
+    query = TreeSitterSymbolExtractor.get_query(".swift")
+    if not parser or not query:
+        pytest.skip("Swift parser or query not available in this environment")
+
+    symbols = TreeSitterSymbolExtractor.extract_symbols(".swift", SWIFT_SAMPLE)
+    names = {s["name"] for s in symbols}
+    types = {s["type"] for s in symbols}
+    animal_symbols = [s for s in symbols if s["name"] == "Animal"]
+
+    assert "Animal" in names
+    assert "Point" in names
+    assert "Direction" in names
+    assert "Worker" in names
+    assert "Drawable" in names
+    assert "StringMap" in names
+    assert "greet" in names
+    assert "init" in names
+
+    assert len(animal_symbols) == 2
+    assert {s["type"] for s in animal_symbols} == {"class", "extension"}
+
+    assert "class" in types
+    assert "actor" in types
+    assert "struct" in types
+    assert "enum" in types
+    assert "extension" in types
+    assert "protocol" in types
+    assert "typealias" in types
+    assert "function" in types
+    assert "initializer" in types
+
+
+def test_swift_in_supported_languages():
+    supported = TreeSitterSymbolExtractor.list_supported_languages()
+    assert "swift" in supported
+    assert ".swift" in supported["swift"]

tests/test_symbol_extraction_multilang.py

@@ -9,6 +9,7 @@
     ".java": "class Bar { void foo() {} }\n",
     ".rs": "fn foo() {}\nstruct Bar;\n",
     ".zig": "pub fn foo() void {}\npub const Bar = struct {};\n",
+    ".swift": "func foo() -> Int { return 42 }\nclass Bar {}\n",
 }
 
 

tests/test_tree_sitter_languages.py

@@ -12,6 +12,7 @@
     "c": b"int foo() { return 42; }\n",
     "dart": b"int foo() { return 42; }\n",
     "zig": b"pub fn foo() void { }\n",
+    "swift": b"func foo() -> Int { return 42 }\n",
 }