Create your DSL with Kotlin
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The document discusses how to create a domain-specific language (DSL) with Kotlin. It explains that a DSL is specialized for a particular application domain. Kotlin is well-suited for creating DSLs because it features extensions, higher-order functions, and lambda receivers that allow for flexible and readable code. The document then demonstrates a DSL for defining UI settings, with rules that allow defining setting groups and items in a structured way.
Create your DSL with Kotlin
- 1. Create your DSL with Kotlin
- 2. 自己紹介 汪 永興 LINE Fukuoka 株式会社 開発Cチーム所属 Kotlinが大好きです ワン ヨンシン (Freddie)
- 3. Create your DSL with Kotlin Agenda ・What’s DSL ・Why Kotlin is easy to create DSL ・The ”Setting UI” DSL
- 4. Create your DSL with Kotlin Domain Specific Language ・It is specialized to a particular application domain Purpose
- 5. Create your DSL with Kotlin Why DSL • Improve Development Productivity • Flexible design • Code readability
- 6. Create your DSL with Kotlin DSL in real world ・SQL ・Regular Expression ・Gradle
- 7. Create your DSL with Kotlin Kotlin DSL in real world • anko • kotlintest • Spring Framework
- 8. Why Kotlin is easy to create DSL
- 9. Create your DSL with Kotlin Main features in Kotlin To support creating DSL easily • Extension • Higher-Order functions • Lambda with receiver
- 10. Create your DSL with Kotlin Extension fun Context.getResIdFromAttr(attr: Int): Int { val value = TypedValue() theme.resolveAttribute(attr, value, true) return value.resourceId } val resId = context.getResIdFromAttr(R.attr.selectableItemBacktround) fun Context.getResIdFromAttr(attr: Int): Int { val value = TypedValue() theme.resolveAttribute(attr, value, true) return value.resourceId } fun Context.getResIdFromAttr(attr: Int): Int { val value = TypedValue() theme.resolveAttribute(attr, value, true) return value.resourceId }
- 11. Create your DSL with Kotlin Higher-Order functions Takes functions as parameter fun <T> lock(lock: Lock, body: () -> T): T { lock.lock() try { return body() } finally { lock.unlock() } } val result = lock (lock, { someResources.operation() } )
- 12. Create your DSL with Kotlin Lambda with receiver fun buildString(action: StringBuilder.() -> Unit): String { val sb = StringBuilder() sb.action() return sb.toString() } buildString {// It is syntax sugar for lambda parameter this.append(“test”) this.append(“test”) //’this’ is StringBuilder } fun buildString(action: StringBuilder.() -> Unit): String { val sb = StringBuilder() sb.action() return sb.toString() }
- 13. The Setting DSL
- 14. Create your DSL with Kotlin Characteristic of Setting UI ・Structured items ・Variable appearance
- 15. Create your DSL with Kotlin
- 16. Create your DSL with Kotlin The syntax settings { settingGroup { settingItem { … } … } } settings { settingGroup { settingItem { … } … } } settings { settingGroup { settingItem { … } … } } Rule1: settings is the root of the UI layoutRule2: settings includes settingGroupRule3: settingGroup includes settingItem
- 17. Create your DSL with Kotlin Setting class Settings(ctx: Context) : _ScrollView(ctx) { internal val rootContainer = verticalLayout().lparams(width = matchParent, height = wrapContent) fun addGroup(group: SettingGroup) { rootContainer.addView(group) } }
- 18. Create your DSL with Kotlin Rule1 inline fun ViewManager.settings(init: Settings.() -> Unit): Setting { … val settings = Settings(ctx) settings.init() this.addView(settings) return settings } inline fun ViewManager.settings(init: Settings.() -> Unit): Setting { … val settings = Settings(ctx) settings.init() this.addView(settings) return settings } inline fun ViewManager.settings(init: Settings.() -> Unit): Setting { … val settings = Settings(ctx) settings.init() this.addView(settings) return settings } settings { //init() settingGroup { settingItem { … } … } }
- 19. Create your DSL with Kotlin SettingGroup class SettingGroup(ctx: Context) : _LinearLayout(ctx) { var title: String … }
- 20. Create your DSL with Kotlin Rule2 inline fun Settings.settingGroup(init: SettingGroup.() -> Unit): SettingGroup { val settingGroup = SettingGroup(this.context) settingGroup.init() … this.addGroup(settingGroup) return settingGroup } inline fun Settings.settingGroup(init: SettingGroup.() -> Unit): SettingGroup { val settingGroup = SettingGroup(this.context) settingGroup.init() … this.addGroup(settingGroup) return settingGroup } inline fun Settings.settingGroup(init: SettingGroup.() -> Unit): SettingGroup { val settingGroup = SettingGroup(this.context) settingGroup.init() … this.addGroup(settingGroup) return settingGroup }
- 21. Create your DSL with Kotlin SettingItem class SettingItem(ctx: Context, …) : _LinearLayout(ctx) { var leftIconResId: Int? var rightIconResId: Int? var title: String var description: String … }
- 22. Create your DSL with Kotlin Rule3 inline fun SettingGroup.settingItem(…, init: SettingItem.() -> Unit): SettingItem { … val settingItem = SettingItem(ctx, …) settingItem.init() this.addView(settingItem) return settingItem } inline fun SettingGroup.settingItem(…, init: SettingItem.() -> Unit): SettingItem { … val settingItem = SettingItem(ctx, …) settingItem.init() this.addView(settingItem) return settingItem } inline fun SettingGroup.settingItem(…, init: SettingItem.() -> Unit): SettingItem { … val settingItem = SettingItem(ctx, …) settingItem.init() this.addView(settingItem) return settingItem }
- 23. Create your DSL with Kotlin DEMO Time! https://github.com/wangyung/android-setting-ui-dsl
- 24. Create your DSL with Kotlin Summary ・It is very easy to create custom DSL with Kotlin ・We can use DSL to write readable, maintainable code very easily
- 25. Q&A
Editor's Notes
- #3: 簡単な挨拶 みなさんこんばんは。 私はフレディです。 よろしくお願いします！ 今日のTopicはKotlinで 自分のDSLを作るっていうことです。
- #4: まず簡単に自己紹介させていただきます。 私の名前は汪永興、 nicknameは Freddie それからみんながよくフレディと呼ばれています。 二年間にAndroid engineerとしてLINE Fukuokaで働いていて、来週からLINE京都に転勤します。
- #5: before start Kotlinを聞いたことがある方はいらしゃいますか？ Kotlinを使っている方 KotlinでDSLを作った方 Agenda: 1. DSLとはなにか、 2. なぜコトリンはDSLを作りやすいか、 3. 最後にUIセッティングのDSLについてです
- #6: 今から英語を使います…w
- #7: 使うのか？ 効率よくする 読みやすくする
- #9: anko: For android UI layout kotlintest: For writing unit tests Spring Framework: Bean creation, routing
- #10: 説明します
- #14: Talk about the syntax sugar