Merge pull request #153 from ReactiveCocoa/as-labelled-pipe

Proposal: Label the output and input ends of Signal.pipe()

Author: mdiep

Sources/Signal.swift

@@ -265,19 +265,20 @@ public final class Signal<Value, Error: Swift.Error> {
 		}
 	}
 
-	/// Create a Signal that will be controlled by sending events to the given
-	/// observer.
+	/// Create a `Signal` that will be controlled by sending events to an
+	/// input observer.
 	///
-	/// - note: The Signal will remain alive until a terminating event is sent
-	///         to the observer, or until it has no observer if it is not
-	///         retained.
+	/// - note: The `Signal` will remain alive until a terminating event is sent
+	///         to the input observer, or until it has no observers and there
+	///         are no strong references to it.
 	///
 	/// - parameters:
 	///   - disposable: An optional disposable to associate with the signal, and
 	///                 to be disposed of when the signal terminates.
 	///
-	/// - returns: A tuple made of signal and observer.
-	public static func pipe(disposable: Disposable? = nil) -> (Signal, Observer) {
+	/// - returns: A tuple of `output: Signal`, the output end of the pipe,
+	///            and `input: Observer`, the input end of the pipe.
+	public static func pipe(disposable: Disposable? = nil) -> (output: Signal, input: Observer) {
 		var observer: Observer!
 		let signal = self.init { innerObserver in
 			observer = innerObserver

Tests/ReactiveSwiftTests/FlattenSpec.swift

@@ -12,7 +12,7 @@ import Quick
 import ReactiveSwift
 
 private extension SignalProtocol {
-	typealias Pipe = (signal: Signal<Value, Error>, observer: Observer<Value, Error>)
+	typealias Pipe = (output: Signal<Value, Error>, input: Observer<Value, Error>)
 }
 
 private typealias Pipe = Signal<SignalProducer<Int, TestError>, TestError>.Pipe
@@ -26,7 +26,7 @@ class FlattenSpec: QuickSpec {
 
 				beforeEach {
 					pipe = Signal.pipe()
-					disposable = pipe.signal
+					disposable = pipe.output
 						.flatten(flattenStrategy)
 						.observe { _ in }
 				}
@@ -40,25 +40,25 @@ class FlattenSpec: QuickSpec {
 
 					beforeEach {
 						disposed = false
-						pipe.observer.send(value: SignalProducer<Int, TestError> { _, disposable in
+						pipe.input.send(value: SignalProducer<Int, TestError> { _, disposable in
 							disposable += ActionDisposable {
 								disposed = true
 							}
 						})
 					}
 
 					it("should dispose inner signals when outer signal interrupted") {
-						pipe.observer.sendInterrupted()
+						pipe.input.sendInterrupted()
 						expect(disposed) == true
 					}
 
 					it("should dispose inner signals when outer signal failed") {
-						pipe.observer.send(error: .default)
+						pipe.input.send(error: .default)
 						expect(disposed) == true
 					}
 
 					it("should not dispose inner signals when outer signal completed") {
-						pipe.observer.sendCompleted()
+						pipe.input.sendCompleted()
 						expect(disposed) == false
 					}
 				}