Add Swift Package Manager Support

Package.swift

@@ -0,0 +1,24 @@
+// swift-tools-version:5.3
+
+
+import PackageDescription
+
+let package = Package(
+    name: "Antlr4",
+    products: [
+        .library(
+            name: "Antlr4",
+            type: .static,
+            targets: ["Antlr4"]),
+    ],
+    targets: [
+        .target(
+            name: "Antlr4",
+            dependencies: [],
+            path: "./runtime/Swift/Sources/Antlr4"),
+        .testTarget(
+            name: "Antlr4Tests",
+            dependencies: ["Antlr4"],
+            path:"./runtime/Swift/Tests/Antlr4Tests"),
+    ]
+)

contributors.txt

@@ -290,3 +290,4 @@ YYYY/MM/DD, github id, Full name, email
 2021/02/27, khmarbaise, Karl Heinz Marbaise, [email protected]
 2021/03/02, hackeris
 2021/03/03, xTachyon, Damian Andrei, [email protected]
+2021/03/22, 100mango, Fangqiu Fang, [email protected]

doc/swift-target.md

@@ -135,30 +135,11 @@ The runtime and generated grammar should now build correctly.
 
 ### Swift Package Manager Projects
 
-Since we cannot have a separate repository for Swift target (see issue [#1774](https://github.com/antlr/antlr4/issues/1774)), 
-and Swift is currently not ABI stable. We currently support support SPM-based
-projects by creating temporary local repository.
+add Antlr4 as a dependency to your `Package.swift` file. For more information, please see the [Swift Package Manager documentation](https://github.com/apple/swift-package-manager/tree/master/Documentation).
 
-For people using [Swift Package Manager](https://swift.org/package-manager/),
-the __boot.py__ script supports generating local repository that can be used
-as a dependency to your project. Simply run:
-
-```
-python boot.py --gen-spm-module
+```swift
+.package(name: "Antlr4", url: "https://github.com/antlr/antlr4", from: "4.9.3"
 ```
-
-The prompt will show something like below:
-
-<img src=images/gen_spm_module.png width="800">
-
-Put the SPM directive that contains the url to temporary repository to your 
-project's Package.swift. And run `swift build` in your project.
-
-The project is generated in your system's `/tmp/` directory, if you find it
-inconvenient, consider copy that generated ANTLR repository to some place 
-that won't be cleaned automatically and update `url` parameter in your 
-`Package.swift` file.
-
 ## Swift access levels
 
 You may use the `accessLevel` option to control the access levels on generated

runtime/Swift/boot.py

@@ -98,6 +98,7 @@ def swift_test():
     Run unit tests.
     """
     generate_parser()
+    check_call(["cd","./../.."])
     check_call(["swift", "test"])