Support Swift versions 3.1 through 4.1

.travis.yml

@@ -1,10 +1,24 @@
-os:
-- linux
-- osx
-language: generic
-sudo: required
-dist: trusty
-osx_image: xcode9
+matrix:
+  include:
+    - os: linux
+      language: generic
+      sudo: required
+      dist: trusty
+      env: SWIFT_VERSION=3.1.1
+    - os: linux
+      language: generic
+      sudo: required
+      dist: trusty
+    - os: osx
+      language: generic
+      sudo: required
+      osx_image: xcode8.3
+      env: SWIFT_VERSION=3.1.1
+    - os: osx
+      language: generic
+      sudo: required
+      osx_image: xcode9
+
 install:
 - eval "$(curl -sL https://gist.githubusercontent.com/kylef/5c0475ff02b7c7671d2a/raw/9f442512a46d7a2af7b850d65a7e9bd31edfb09b/swiftenv-install.sh)"
 script:

Package.swift

@@ -1,17 +1,9 @@
-// swift-tools-version:4.0
 import PackageDescription
 
 let package = Package(
   name: "PathKit",
-  products: [
-    .library(name: "PathKit", targets: ["PathKit"]),
-  ],
   dependencies: [
-    .package(url:"https://github.com/kylef/Spectre.git", .upToNextMinor(from:"0.8.0"))
-  ],
-  targets: [
-    .target(name: "PathKit", dependencies: [], path: "Sources"),
-    .testTarget(name: "PathKitTests", dependencies: ["PathKit", "Spectre"], path:"Tests/PathKitTests")
-  ],
-  swiftLanguageVersions: [3]
+    // https://github.com/apple/swift-package-manager/pull/597
+    .Package(url: "https://github.com/kylef/Spectre.git", majorVersion: 0, minor: 7),
+  ]
 )

Package@swift-4.swift

@@ -0,0 +1,16 @@
+// swift-tools-version:4.0
+import PackageDescription
+
+let package = Package(
+  name: "PathKit",
+  products: [
+    .library(name: "PathKit", targets: ["PathKit"]),
+  ],
+  dependencies: [
+    .package(url:"https://github.com/kylef/Spectre.git", .upToNextMinor(from:"0.8.0"))
+  ],
+  targets: [
+    .target(name: "PathKit", dependencies: [], path: "Sources"),
+    .testTarget(name: "PathKitTests", dependencies: ["PathKit", "Spectre"], path:"Tests/PathKitTests")
+  ]
+)

Sources/PathKit.swift

@@ -42,7 +42,11 @@ public struct Path {
       path = "."
     } else if components.first == Path.separator && components.count > 1 {
       let p = components.joined(separator: Path.separator)
+#if swift(>=4.0)
+      path = String(p[p.index(after: p.startIndex)...])
+#else
       path = p.substring(from: p.characters.index(after: p.startIndex))
+#endif
     } else {
       path = components.joined(separator: Path.separator)
     }
@@ -276,10 +280,10 @@ extension Path {
     guard Path.fileManager.fileExists(atPath: normalize().path, isDirectory: &directory) else {
       return false
     }
-#if os(Linux)
-    return directory
-#else
+#if !os(Linux) || swift(>=4.1)
     return directory.boolValue
+#else
+    return directory
 #endif
   }
 
@@ -295,10 +299,10 @@ extension Path {
     guard Path.fileManager.fileExists(atPath: normalize().path, isDirectory: &directory) else {
       return false
     }
-#if os(Linux)
-  return !directory
-#else
+#if !os(Linux) || swift(>=4.1)
   return !directory.boolValue
+#else
+  return !directory
 #endif
   }
 
@@ -598,13 +602,23 @@ extension Path {
 #else
       let matchc = gt.gl_matchc
 #endif
+#if swift(>=4.1)
+      return (0..<Int(matchc)).compactMap { index in
+        if let path = String(validatingUTF8: gt.gl_pathv[index]!) {
+          return Path(path)
+        }
+
+        return nil
+      }
+#else
       return (0..<Int(matchc)).flatMap { index in
         if let path = String(validatingUTF8: gt.gl_pathv[index]!) {
           return Path(path)
         }
 
         return nil
       }
+#endif
     }
 
     // GLOB_NOMATCH

Tests/PathKitTests/PathKitSpec.swift

@@ -210,10 +210,10 @@ describe("PathKit") {
 
   $0.it("can return the last component without extension") {
     try expect(Path("a/b/c.d").lastComponentWithoutExtension) == "c"
-    #if os(Linux) // no longer necessary after Swift 4.1
-        try expect(Path("a/..").lastComponentWithoutExtension) == "."
-    #else
+    #if !os(Linux) || swift(>=4.1)
         try expect(Path("a/..").lastComponentWithoutExtension) == ".."
+    #else
+        try expect(Path("a/..").lastComponentWithoutExtension) == "."
     #endif
   }