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Add AsyncStream convenience initializer
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,39 @@ | ||
| // | ||
| // AsyncStream+Extensions.swift | ||
| // Aware | ||
| // | ||
| // Created by Joshua Peek on 3/24/24. | ||
| // | ||
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| extension AsyncStream { | ||
| /// Annoying wrapper to get | ||
| /// typealias Yield = @discardableResult (Element) -> Continuation.YieldResult | ||
| struct Yield: Sendable { | ||
| private let continuation: Continuation | ||
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| fileprivate init(continuation: Continuation) { | ||
| self.continuation = continuation | ||
| } | ||
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| @discardableResult | ||
| func callAsFunction(_ value: Element) -> Continuation.YieldResult { | ||
| continuation.yield(value) | ||
| } | ||
| } | ||
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| init( | ||
| _ elementType: Element.Type = Element.self, | ||
| bufferingPolicy limit: Continuation.BufferingPolicy = .unbounded, | ||
| _ build: @Sendable @escaping (Yield) async -> Void | ||
| ) { | ||
| self.init(elementType, bufferingPolicy: limit) { continuation in | ||
| let task = Task { | ||
| await build(Yield(continuation: continuation)) | ||
| continuation.finish() | ||
| } | ||
| continuation.onTermination = { _ in | ||
| task.cancel() | ||
| } | ||
| } | ||
| } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,47 @@ | ||
| import XCTest | ||
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| @testable import Aware | ||
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| final class AsyncStreamTests: XCTestCase { | ||
| func testSimpleAsyncStream() async throws { | ||
| @Sendable func answer() async -> Int { | ||
| 42 | ||
| } | ||
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| let stream = AsyncStream { [answer] yield in | ||
| let n = await answer() | ||
| yield(n) | ||
| yield(n + 1) | ||
| yield(n + 2) | ||
| } | ||
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| var numbers: [Int] = [] | ||
| for await n in stream { | ||
| numbers.append(n) | ||
| } | ||
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| XCTAssertEqual(numbers, [42, 43, 44]) | ||
| } | ||
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| func testMapAsyncStream() async throws { | ||
| let stream1 = AsyncStream { continuation in | ||
| continuation.yield(1) | ||
| continuation.yield(2) | ||
| continuation.yield(3) | ||
| continuation.finish() | ||
| } | ||
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| let stream2 = AsyncStream { yield in | ||
| for await n in stream1 { | ||
| yield(n * 2) | ||
| } | ||
| } | ||
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| var numbers: [Int] = [] | ||
| for await n in stream2 { | ||
| numbers.append(n) | ||
| } | ||
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| XCTAssertEqual(numbers, [2, 4, 6]) | ||
| } | ||
| } |