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Add Swift macro (requires Swift v5.9) (#58)
* Add Swift macro (requires Swift v5.9) * Update Swift workflow * Fix expandable section in readme * Use initializers * Throw error instead of returning empty array * Do not abbreviate enumeration * Update file header comments * Fix tests * Utilize transform instead of for loop * Remove local variables * Improve formatting * Use throwing initializer
1 parent 0f79642 commit 00ee8f4

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-126
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‎.github/workflows/swift.yml

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branches: [ main ]
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env:
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DEVELOPER_DIR: /Applications/Xcode_12.5.1.app/Contents/Developer
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DEVELOPER_DIR: /Applications/Xcode_15.0.app/Contents/Developer
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jobs:
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build_and_test:
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runs-on: macos-11
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swift:
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name: Swift
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runs-on: macos-13
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steps:
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- uses: actions/checkout@v2
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- name: Checkout source
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uses: actions/checkout@v3
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- name: Build
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run: swift build -v
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- name: Run tests
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run: swift build -v -Xswiftc -warnings-as-errors
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- name: Test
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run: swift test -v

‎Package.resolved

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{
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"object": {
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"pins": [
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{
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"package": "CwlCatchException",
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"repositoryURL": "https://github.com/mattgallagher/CwlCatchException.git",
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"state": {
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"branch": null,
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"revision": "682841464136f8c66e04afe5dbd01ab51a3a56f2",
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"version": "2.1.0"
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}
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},
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{
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"package": "CwlPreconditionTesting",
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"repositoryURL": "https://github.com/mattgallagher/CwlPreconditionTesting.git",
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"state": {
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"branch": null,
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"revision": "02b7a39a99c4da27abe03cab2053a9034379639f",
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"version": "2.0.0"
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}
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},
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{
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"package": "Nimble",
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"repositoryURL": "https://github.com/Quick/Nimble.git",
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"state": {
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"branch": null,
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"revision": "af1730dde4e6c0d45bf01b99f8a41713ce536790",
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"version": "9.2.0"
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}
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"pins" : [
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{
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"identity" : "cwlcatchexception",
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"kind" : "remoteSourceControl",
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"location" : "https://github.com/mattgallagher/CwlCatchException.git",
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"state" : {
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"revision" : "3b123999de19bf04905bc1dfdb76f817b0f2cc00",
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"version" : "2.1.2"
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}
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]
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},
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"version": 1
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},
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{
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"identity" : "cwlpreconditiontesting",
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"kind" : "remoteSourceControl",
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"location" : "https://github.com/mattgallagher/CwlPreconditionTesting.git",
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"state" : {
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"revision" : "dc9af4781f2afdd1e68e90f80b8603be73ea7abc",
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"version" : "2.2.0"
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}
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},
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{
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"identity" : "nimble",
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"kind" : "remoteSourceControl",
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"location" : "https://github.com/Quick/Nimble.git",
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"state" : {
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"revision" : "efe11bbca024b57115260709b5c05e01131470d0",
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"version" : "13.2.1"
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}
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},
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{
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"identity" : "swift-syntax",
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"kind" : "remoteSourceControl",
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"location" : "https://github.com/apple/swift-syntax.git",
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"state" : {
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"revision" : "64889f0c732f210a935a0ad7cda38f77f876262d",
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"version" : "509.1.1"
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}
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}
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],
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"version" : 2
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}

‎[email protected]

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// swift-tools-version:5.9
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import PackageDescription
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import CompilerPluginSupport
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let package = Package(
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name: "StateMachine",
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platforms: [
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.macOS(.v10_15),
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.iOS(.v13),
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.tvOS(.v13),
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.watchOS(.v5),
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],
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products: [
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.library(
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name: "StateMachine",
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targets: ["StateMachine"]),
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],
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dependencies: [
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.package(
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url: "https://github.com/apple/swift-syntax.git",
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from: "509.1.0"),
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.package(
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url: "https://github.com/Quick/Nimble.git",
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from: "13.2.0"),
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],
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targets: [
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.target(
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name: "StateMachine",
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dependencies: ["StateMachineMacros"],
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path: "Swift/Sources/StateMachine"),
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.macro(
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name: "StateMachineMacros",
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dependencies: [
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.product(name: "SwiftSyntaxMacros", package: "swift-syntax"),
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.product(name: "SwiftCompilerPlugin", package: "swift-syntax"),
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],
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path: "Swift/Sources/StateMachineMacros"),
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.testTarget(
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name: "StateMachineTests",
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dependencies: [
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"StateMachine",
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"StateMachineMacros",
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.product(name: "SwiftSyntaxMacros", package: "swift-syntax"),
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.product(name: "SwiftSyntaxMacrosTestSupport", package: "swift-syntax"),
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"Nimble",
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],
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path: "Swift/Tests/StateMachineTests"),
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]
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)

‎README.md

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@@ -16,7 +16,7 @@ The examples below create a `StateMachine` from the following state diagram for
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Define states, events and side effects:
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~~~kotlin
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```kotlin
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sealed class State {
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object Solid : State()
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object Liquid : State()
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object LogVaporized : SideEffect()
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object LogCondensed : SideEffect()
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}
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~~~
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```
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Initialize state machine and declare state transitions:
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~~~kotlin
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```kotlin
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val stateMachine = StateMachine.create<State, Event, SideEffect> {
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initialState(State.Solid)
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state<State.Solid> {
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}
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}
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}
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~~~
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```
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Perform state transitions:
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~~~kotlin
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```kotlin
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assertThat(stateMachine.state).isEqualTo(Solid)
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// When
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StateMachine.Transition.Valid(Solid, OnMelted, Liquid, LogMelted)
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)
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then(logger).should().log(ON_MELTED_MESSAGE)
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~~~
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```
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## Swift Usage
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Define states, events and side effects:
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```swift
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enum State: StateMachineHashable {
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@StateMachineHashable
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enum State {
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case solid, liquid, gas
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}
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enum Event: StateMachineHashable {
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@StateMachineHashable
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enum Event {
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case melt, freeze, vaporize, condense
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}
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expect(logger).to(log(Message.melted))
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```
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### Swift Enumerations with Associated Values
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#### Pre-Swift 5.9 Compatibility
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<details>
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<summary>Expand</summary>
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Due to Swift enumerations (as opposed to sealed classes in Kotlin),
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any `State` or `Event` enumeration defined with associated values will require [boilerplate implementation](https://github.com/Tinder/StateMachine/blob/c5c8155d55db5799190d9a06fbc31263c76c80b6/Swift/Tests/StateMachineTests/StateMachine_Turnstile_Tests.swift#L198-L260) for `StateMachineHashable` conformance.
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<br>
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The easiest way to create this boilerplate is by using the [Sourcery](https://github.com/krzysztofzablocki/Sourcery) Swift code generator along with the [AutoStateMachineHashable stencil template](https://github.com/Tinder/StateMachine/blob/main/Swift/Resources/AutoStateMachineHashable.stencil) provided in this repository. Once the codegen is setup and configured, adopt `AutoStateMachineHashable` instead of `StateMachineHashable` for the `State` and/or `Event` enumerations.
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This information is only applicable to Swift versions older than `5.9`:
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> ### Swift Enumerations with Associated Values
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>
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> Due to Swift enumerations (as opposed to sealed classes in Kotlin), any `State` or `Event` enumeration defined with associated values will require [boilerplate implementation](https://github.com/Tinder/StateMachine/blob/c5c8155d55db5799190d9a06fbc31263c76c80b6/Swift/Tests/StateMachineTests/StateMachine_Turnstile_Tests.swift#L198-L260) for `StateMachineHashable` conformance.
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>
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> The easiest way to create this boilerplate is by using the [Sourcery](https://github.com/krzysztofzablocki/Sourcery) Swift code generator along with the [AutoStateMachineHashable stencil template](https://github.com/Tinder/StateMachine/blob/main/Swift/Resources/AutoStateMachineHashable.stencil) provided in this repository. Once the codegen is setup and configured, adopt `AutoStateMachineHashable` instead of `StateMachineHashable` for the `State` and/or `Event` enumerations.
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</details>
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## Examples
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Thanks to [@nvinayshetty](https://github.com/nvinayshetty), you can visualize your state machines right in the IDE using the [State Arts](https://github.com/nvinayshetty/StateArts) Intellij [plugin](https://plugins.jetbrains.com/plugin/12193-state-art).
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## License
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~~~
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```
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Copyright (c) 2018, Match Group, LLC
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All rights reserved.
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@@ -256,4 +269,4 @@ LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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~~~
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```

‎Swift/Sources/StateMachine/Macros.swift

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//
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// Copyright (c) 2024, Match Group, LLC
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// BSD License, see LICENSE file for details
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//
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@attached(extension,
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conformances: StateMachineHashable,
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names: named(hashableIdentifier), named(HashableIdentifier), named(associatedValue))
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public macro StateMachineHashable() = #externalMacro(module: "StateMachineMacros",
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type: "StateMachineHashableMacro")

‎Swift/Sources/StateMachineMacros/Macros/StateMachineHashableMacro.swift

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//
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// Copyright (c) 2019, Match Group, LLC
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// BSD License, see LICENSE file for details
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//
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import SwiftSyntax
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import SwiftSyntaxBuilder
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import SwiftSyntaxMacros
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public struct StateMachineHashableMacro: ExtensionMacro {
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public static func expansion(
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of node: AttributeSyntax,
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attachedTo declaration: some DeclGroupSyntax,
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providingExtensionsOf type: some TypeSyntaxProtocol,
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conformingTo protocols: [TypeSyntax],
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in context: some MacroExpansionContext
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) throws -> [ExtensionDeclSyntax] {
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guard let enumDecl: EnumDeclSyntax = .init(declaration)
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else { throw StateMachineHashableMacroError.typeMustBeEnumeration }
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let elements: [EnumCaseElementSyntax] = enumDecl
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.memberBlock
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.members
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.compactMap(MemberBlockItemSyntax.init)
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.map(\.decl)
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.compactMap(EnumCaseDeclSyntax.init)
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.flatMap(\.elements)
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guard !elements.isEmpty
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else { throw StateMachineHashableMacroError.enumerationMustHaveCases }
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let enumCases: [String] = elements
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.map(\.name.text)
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.map { "case \($0)" }
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let hashableIdentifierCases: [String] = elements
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.map(\.name.text)
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.map { "case .\($0):\nreturn .\($0)" }
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let associatedValueCases: [String] = elements.map { element in
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if let parameters: EnumCaseParameterListSyntax = element.parameterClause?.parameters, !parameters.isEmpty {
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if parameters.count > 1 {
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let associatedValues: String = (1...parameters.count)
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.map { "value\($0)" }
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.joined(separator: ", ")
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return """
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case let .\(element.name.text)(\(associatedValues)):
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return (\(associatedValues))
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"""
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} else {
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return """
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case let .\(element.name.text)(value):
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return (value)
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"""
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}
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} else {
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return """
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case .\(element.name.text):
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return ()
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"""
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}
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}
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let node: SyntaxNodeString = """
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extension \(type): StateMachineHashable {
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enum HashableIdentifier {
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\(raw: enumCases.joined(separator: "\n"))
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}
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var hashableIdentifier: HashableIdentifier {
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switch self {
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\(raw: hashableIdentifierCases.joined(separator: "\n"))
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}
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}
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var associatedValue: Any {
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switch self {
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\(raw: associatedValueCases.joined(separator: "\n"))
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}
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}
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}
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"""
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return try [ExtensionDeclSyntax(node)]
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}
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}

‎Swift/Sources/StateMachineMacros/Macros/StateMachineHashableMacroError.swift

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//
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// Copyright (c) 2019, Match Group, LLC
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// BSD License, see LICENSE file for details
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//
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public enum StateMachineHashableMacroError: Error, CustomStringConvertible {
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case typeMustBeEnumeration
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case enumerationMustHaveCases
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public var description: String {
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switch self {
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case .typeMustBeEnumeration:
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return "Type Must Be Enumeration"
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case .enumerationMustHaveCases:
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return "Enumeration Must Have Cases"
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}
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}
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}

‎Swift/Sources/StateMachineMacros/StateMachineMacros.swift

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//
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// Copyright (c) 2019, Match Group, LLC
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// BSD License, see LICENSE file for details
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//
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#if canImport(SwiftCompilerPlugin)
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import SwiftCompilerPlugin
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import SwiftSyntaxMacros
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@main
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internal struct StateMachineMacros: CompilerPlugin {
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internal let providingMacros: [Macro.Type] = [StateMachineHashableMacro.self]
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}
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#endif

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