Better Swift Concurrenty Integration

Author: srdanrasic

Sources/Signal.swift

@@ -221,11 +221,39 @@ extension Signal where Error == Swift.Error {
     public init(catching body: @escaping () throws -> Element) {
         self = Signal(result: Result(catching: body))
     }
+    
+    /// Create a new signal by awaiting an async closure.
+    @available(macOS 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
+    public init(await produce: @escaping () async throws -> Element) {
+        self.init { observer in
+            let task = Task {
+                do {
+                    let element = try await produce()
+                    observer.receive(lastElement: element)
+                } catch {
+                    observer.receive(completion: .failure(error))
+                }
+            }
+            return BlockDisposable(task.cancel)
+        }
+    }
 }
 
 #if !XCFRAMEWORK
 
 extension Signal where Error == Never {
+    
+    /// Create a new signal by awaiting an async closure.
+    @available(macOS 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
+    public init(await produce: @escaping () async -> Element) {
+        self.init { observer in
+            let task = Task {
+                let element = await produce()
+                observer.receive(lastElement: element)
+            }
+            return BlockDisposable(task.cancel)
+        }
+    }
 
     /// Create a new signal and assign its next element observer to the given variable.
     /// Calling the closure assigned to the varaible will send the next element on the signal.

Sources/SignalProtocol+Async.swift

@@ -0,0 +1,107 @@
+//
+//  The MIT License (MIT)
+//
+//  Copyright (c) 2016-2019 Srdan Rasic (@srdanrasic)
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to deal
+//  in the Software without restriction, including without limitation the rights
+//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//  copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+//  THE SOFTWARE.
+//
+
+import Foundation
+
+@available(macOS 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
+extension SignalProtocol where Error == Never {
+
+    public func toAsyncStream() -> AsyncStream<Element> {
+        AsyncStream<Element> { continuation in
+            let disposable = self.observe { event in
+                switch event {
+                case .next(let element):
+                    continuation.yield(element)
+                case .completed:
+                    continuation.finish()
+                }
+            }
+            continuation.onTermination = { @Sendable _ in
+                disposable.dispose()
+            }
+        }
+    }
+}
+
+@available(macOS 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
+extension SignalProtocol where Error == Swift.Error {
+
+    public func toAsyncThrowingStream() -> AsyncThrowingStream<Element, Error> {
+        AsyncThrowingStream<Element, Error> { continuation in
+            let disposable = self.observe { event in
+                switch event {
+                case .next(let element):
+                    continuation.yield(element)
+                case .failed(let error):
+                    continuation.finish(throwing: error)
+                case .completed:
+                    continuation.finish()
+                }
+            }
+            continuation.onTermination = { @Sendable _ in
+                disposable.dispose()
+            }
+        }
+    }
+}
+
+@available(macOS 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
+extension AsyncSequence {
+
+    public func toSignal() -> Signal<Element, Swift.Error> {
+        Signal<Element, Swift.Error> { observer in
+            let task = Task {
+                do {
+                    for try await element in self {
+                        observer.receive(element)
+                    }
+                    observer.receive(completion: .finished)
+                } catch {
+                    observer.receive(completion: .failure(error))
+                }
+            }
+            return BlockDisposable(task.cancel)
+        }
+    }
+}
+
+@available(macOS 15.0, iOS 18.0, watchOS 11.0, tvOS 18.0, *)
+extension AsyncSequence {
+    
+    public func toFullyTypedSignal() -> Signal<Element, Failure> {
+        Signal<Element, Failure> { observer in
+            let task = Task {
+                do {
+                    for try await element in self {
+                        observer.receive(element)
+                    }
+                    observer.receive(completion: .finished)
+                } catch let error as Failure {
+                    observer.receive(completion: .failure(error))
+                }
+            }
+            return BlockDisposable(task.cancel)
+        }
+    }
+}