Swift 4

.travis.yml

@@ -1,6 +1,6 @@
 language: objective-c
 osx_image: xcode8.3
-before_install: 
+before_install:
   - brew uninstall carthage
   - HOMEBREW_NO_AUTO_UPDATE=1 brew install https://raw.githubusercontent.com/Homebrew/homebrew-core/6ae4f69a652fb0ecb102b0c9216378679a4f1b92/Formula/carthage.rb # 0.22.0
 install: true
@@ -9,7 +9,7 @@ branches:
     - master
     # Credit: @Omnikron13, https://github.com/mojombo/semver/issues/32
     - /^(\d+\.\d+\.\d+)(?:-([0-9A-Za-z-]+(?:\.[0-9A-Za-z-]+)*))?(?:\+([0-9A-Za-z-]+(?:\.[0-9A-Za-z-]+)*))?$/
-    - /^hotfix-(\d+\.\d+\.\d+)(?:-([0-9A-Za-z-]+(?:\.[0-9A-Za-z-]+)*))?(?:\+([0-9A-Za-z-]+(?:\.[0-9A-Za-z-]+)*))?$/ 
+    - /^hotfix-(\d+\.\d+\.\d+)(?:-([0-9A-Za-z-]+(?:\.[0-9A-Za-z-]+)*))?(?:\+([0-9A-Za-z-]+(?:\.[0-9A-Za-z-]+)*))?$/
 script:
   - script/build
 xcode_workspace: ReactiveSwift.xcworkspace
@@ -55,6 +55,15 @@ jobs:
         submodules: false
       env:
         - JOB=SWIFTPM_DARWIN
+    - before_install:
+        - eval "$(curl -sL https://gist.githubusercontent.com/kylef/5c0475ff02b7c7671d2a/raw/9f442512a46d7a2af7b850d65a7e9bd31edfb09b/swiftenv-install.sh)"
+      script:
+        - swift build
+      git:
+        submodules: false
+      env:
+        - JOB=SWIFT_4
+        - SWIFT_VERSION=DEVELOPMENT-SNAPSHOT-2017-05-29-a
     - os: linux
       language: generic
       sudo: required
@@ -81,7 +90,7 @@ jobs:
     - stage: deploy
       before_install: true
       script: skip
-      deploy: 
+      deploy:
         provider: script
         script: script/gen-docs
         on:

Sources/EventLogger.swift

@@ -27,7 +27,7 @@ public enum LoggingEvent {
 	}
 }
 
-private func defaultEventLog(identifier: String, event: String, fileName: String, functionName: String, lineNumber: Int) {
+public func defaultEventLog(identifier: String, event: String, fileName: String, functionName: String, lineNumber: Int) {
 	print("[\(identifier)] \(event) fileName: \(fileName), functionName: \(functionName), lineNumber: \(lineNumber)")
 }
 
@@ -69,10 +69,10 @@ extension Signal {
 
 		return self.on(
 			failed: log(.failed),
-			completed: log(.completed),
-			interrupted: log(.interrupted),
-			terminated: log(.terminated),
-			disposed: log(.disposed),
+			completed: log(.completed) as ((()) -> Void)?,
+			interrupted: log(.interrupted) as ((()) -> Void)?,
+			terminated: log(.terminated) as ((()) -> Void)?,
+			disposed: log(.disposed) as ((()) -> Void)?,
 			value: log(.value)
 		)
 	}
@@ -106,13 +106,13 @@ extension SignalProducer {
 		}
 
 		return self.on(
-			starting: log(.starting),
-			started: log(.started),
+			starting: log(.starting) as ((()) -> Void)?,
+			started: log(.started) as ((()) -> Void)?,
 			failed: log(.failed),
-			completed: log(.completed),
-			interrupted: log(.interrupted),
-			terminated: log(.terminated),
-			disposed: log(.disposed),
+			completed: log(.completed) as ((()) -> Void)?,
+			interrupted: log(.interrupted) as ((()) -> Void)?,
+			terminated: log(.terminated) as ((()) -> Void)?,
+			disposed: log(.disposed) as ((()) -> Void)?,
 			value: log(.value)
 		)
 	}

Sources/Signal.swift

@@ -2085,7 +2085,7 @@ extension Signal {
 		private let action: (ContiguousArray<Any>) -> Void
 
 		private var hasCompletedAndEmptiedSignal: Bool {
-			return Swift.zip(values, isCompleted).contains(where: { $0.isEmpty && $1 })
+			return Swift.zip(values, isCompleted).contains(where: { $0.0.isEmpty && $0.1 })
 		}
 
 		private var canEmit: Bool {
@@ -2485,7 +2485,7 @@ extension Signal where Value == Bool {
 	///
 	/// - returns: A signal that emits the logical AND results.
 	public func and(_ signal: Signal<Value, Error>) -> Signal<Value, Error> {
-		return self.combineLatest(with: signal).map { $0 && $1 }
+		return self.combineLatest(with: signal).map { $0.0 && $0.1 }
 	}
 
 	/// Create a signal that computes a logical OR between the latest values of `self`
@@ -2496,7 +2496,7 @@ extension Signal where Value == Bool {
 	///
 	/// - returns: A signal that emits the logical OR results.
 	public func or(_ signal: Signal<Value, Error>) -> Signal<Value, Error> {
-		return self.combineLatest(with: signal).map { $0 || $1 }
+		return self.combineLatest(with: signal).map { $0.0 || $0.1 }
 	}
 }
 
@@ -2511,8 +2511,8 @@ extension Signal {
 	/// - returns: A signal which forwards the values from `self` until the given action
 	///            fails.
 	public func attempt(_ action: @escaping (Value) -> Result<(), Error>) -> Signal<Value, Error> {
-		return attemptMap { value in
-			return action(value).map {
+		return attemptMap { value -> Result<Value, Error> in
+			return action(value).map { _ -> Value in
 				return value
 			}
 		}