refactor: Switch to Swift 4.0

Author: kylef

.travis.yml

@@ -4,8 +4,8 @@ os:
 language: generic
 sudo: required
 dist: trusty
-osx_image: xcode8.3
-env: SWIFT_VERSION=3.1.1
+osx_image: xcode9
+env: SWIFT_VERSION=4.0
 install:
 - eval "$(curl -sL https://swiftenv.fuller.li/install.sh)"
 script:

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Commander Changelog
 
+## Master
+
+Switches to Swift 4.0.
+
 ### Bug Fixes
 
 - Better detection of ANSI support in output tty.

Package.swift

@@ -1,8 +1,14 @@
+// swift-tools-version:4.0
+
 import PackageDescription
 
 let package = Package(
   name: "Commander",
   dependencies: [
-    .Package(url: "https://github.com/kylef/Spectre.git", majorVersion: 0, minor: 7),
+    .package(url: "https://github.com/kylef/Spectre.git", from: "0.8.0"),
+  ],
+  targets: [
+    .target(name: "Commander", dependencies: []),
+    .testTarget(name: "CommanderTests", dependencies: ["Commander", "Spectre"]),
   ]
 )

Sources/Commander/ArgumentConvertible.swift

@@ -48,7 +48,7 @@ public protocol ArgumentConvertible : CustomStringConvertible {
 extension String : ArgumentConvertible {
   public init(parser: ArgumentParser) throws {
     if let value = parser.shift() {
-      self.init(value)!
+      self.init(value)
     } else {
       throw ArgumentError.missingValue(argument: nil)
     }

Sources/Commander/ArgumentParser.swift

@@ -57,7 +57,7 @@ public final class ArgumentParser : ArgumentConvertible, CustomStringConvertible
 
         if flags.characters.first == "-" {
           let option = flags[flags.characters.index(after: flags.startIndex)..<flags.endIndex]
-          return .option(option)
+          return .option(String(option))
         }
 
         return .flag(Set(flags.characters))