add concurrency bridge to Promise. (#50)

Co-authored-by: Oguz Yuksel <oguz.yueksel@teufel.de>

Sources/FoundationExtensions/Concurrency/AsyncSequence.swift

@@ -0,0 +1,18 @@
+// Copyright © 2023 Lautsprecher Teufel GmbH. All rights reserved.
+
+import _Concurrency
+
+@available(macOS 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
+extension AsyncSequence {
+
+    /// Returns a new asynchronous sequence that transforms the elements of the sequence using a key path.
+    ///
+    /// This method works as a shortcut for the `map` function, specifically using a key path as the transform function. Each element of the sequence is transformed to the value at the specified key path of the element.
+    ///
+    /// - Parameter kp: A key path that specifies which property value to map from each element in the sequence.
+    /// - Returns: A new asynchronous sequence that contains the transformed elements. Each element is the value at the specified key path of the corresponding element in the original sequence.
+    @inlinable
+    public func map<Value>(_ kp: KeyPath<Element, Value>) -> AsyncMapSequence<Self, Value> {
+        map { $0[keyPath: kp] }
+    }
+}

Sources/FoundationExtensions/Promise/Promise.swift

@@ -73,6 +73,32 @@ extension Publishers {
             }
         }
 
+        public init(_ asyncFunc: @escaping () async throws -> Success) where Failure == Error {
+            self.init { promise in
+                let task = Task {
+                    do {
+                        let result = try await asyncFunc()
+                        promise(.success(result))
+                    } catch {
+                        promise(.failure(error))
+                    }
+                }
+
+                return AnyCancellable { task.cancel() }
+            }
+        }
+
+        public init(_ asyncFunc: @escaping () async -> Success)  where Failure == Never {
+            self.init { promise in
+                let task = Task {
+                    let result = await asyncFunc()
+                    promise(.success(result))
+                }
+
+                return AnyCancellable { task.cancel() }
+            }
+        }
+
         /// This function is called to attach the specified `Subscriber` to this `Publisher` by `subscribe(_:)`
         ///
         /// - SeeAlso: `subscribe(_:)`