Adds Swift version support

Example/Packages/Example/Example.json

@@ -4,6 +4,15 @@
     ".iOS(.v15)",
     ".macOS(.v13)"
   ],
+  "swiftLanguageVersions": [
+      {
+          "version": "5.10",
+          "isToolsVersion": true
+      },
+      {
+          "version": "6.0"
+      }
+  ],
   "products": [
     {
       "productType": "library",

README.md

@@ -52,6 +52,15 @@ Packages should be contained in respective folders inside a packages folder and
 ```json
 {
   "name": "Example",
+  "swiftLanguageVersions": [
+      {
+          "version": "5.10",
+          "isToolsVersion": true
+      },
+      {
+          "version": "6.0"
+      }
+  ],
   "products": [
     {
       "name": "Example",

Sources/Core/SpecGenerator.swift

@@ -57,7 +57,8 @@ final class SpecGenerator {
                     products: partialSpec.products,
                     targets: partialSpec.targets,
                     localBinaryTargets: partialSpec.localBinaryTargets,
-                    remoteBinaryTargets: partialSpec.remoteBinaryTargets)
+                    remoteBinaryTargets: partialSpec.remoteBinaryTargets,
+                    swiftLanguageVersions: partialSpec.swiftLanguageVersions)
     }
 
     private func specURL(for packageName: PackageName) -> URL {

Sources/Models/Spec.swift

@@ -13,6 +13,7 @@ struct Spec: Decodable {
     let targets: [Target]
     let localBinaryTargets: [LocalBinaryTarget]?
     let remoteBinaryTargets: [RemoteBinaryTarget]?
+    let swiftLanguageVersions: [SwiftLanguageVersion]?
 
     init(name: PackageName,
          platforms: [String]?,
@@ -21,7 +22,8 @@ struct Spec: Decodable {
          products: [Product],
          targets: [Target],
          localBinaryTargets: [LocalBinaryTarget]? = nil,
-         remoteBinaryTargets: [RemoteBinaryTarget]? = nil) {
+         remoteBinaryTargets: [RemoteBinaryTarget]? = nil,
+         swiftLanguageVersions: [SwiftLanguageVersion]? = nil) {
         self.name = name
         self.platforms = platforms
         self.localDependencies = localDependencies
@@ -30,6 +32,7 @@ struct Spec: Decodable {
         self.targets = targets
         self.localBinaryTargets = localBinaryTargets
         self.remoteBinaryTargets = remoteBinaryTargets
+        self.swiftLanguageVersions = swiftLanguageVersions
     }
 }
 
@@ -43,7 +46,8 @@ extension Spec {
             "products": products,
             "targets": targets,
             "local_binary_targets": localBinaryTargets,
-            "remote_binary_targets": remoteBinaryTargets
+            "remote_binary_targets": remoteBinaryTargets,
+            "swift_versions": swiftLanguageVersions
         ]
         return values.compactMapValues { $0 }
     }
@@ -190,3 +194,8 @@ struct RemoteBinaryTarget: Decodable {
     let url: String
     let checksum: String
 }
+
+struct SwiftLanguageVersion: Decodable {
+    let version: String
+    let isToolsVersion: Bool?
+}

Templates/Package.stencil

@@ -62,7 +62,15 @@
             checksum: "{{ target.checksum }}"
         ),
 {% endmacro %}
+{% if swift_versions %}
+    {% for swift_version in swift_versions %}
+        {% if swift_version.isToolsVersion %}
+// swift-tools-version: {{ swift_version.version }}
+        {% endif %}
+    {% endfor %}
+{% else %}
 // swift-tools-version: 5.7
+{% endif %}
 
 // This file was automatically generated by PackageGenerator and untracked
 // PLEASE DO NOT EDIT MANUALLY
@@ -115,5 +123,14 @@ let package = Package(
 {% for target in remote_binary_targets %}
     {% call addRemoteBinaryTarget target %}
 {% endfor %}
+{% if swift_versions %}
+    ],
+    swiftLanguageVersions: [
+    {% for swift_version in swift_versions %}
+        .version("{{ swift_version.version }}"),
+    {% endfor %}
+    ]
+{% else %}
     ]
-)
+{% endif %}
+)