---
title: "Kotlin Patterns"
description: "> This file extends the common patterns rule with Kotlin-specific content."
type: skill
canonical_url: https://claudary.paisolsolutions.com/skills/kotlin-patterns
source: "Claudary"
difficulty: intermediate
author: "Claude Code Knowledge Pack"
date: 2026-07-10T11:30:26.149Z
license: CC-BY-4.0
attribution: "Kotlin Patterns — Claudary (https://claudary.paisolsolutions.com/skills/kotlin-patterns)"
---

# Kotlin Patterns
> This file extends the common patterns rule with Kotlin-specific content.

## Overview

---
description: "Kotlin patterns extending common rules"
globs: ["**/*.kt", "**/*.kts", "**/build.gradle.kts"]
alwaysApply: false
---
# Kotlin Patterns

> This file extends the common patterns rule with Kotlin-specific content.

## Sealed Classes

Use sealed classes/interfaces for exhaustive type hierarchies:

```kotlin
sealed class Result<out T> {
    data class Success<T>(val data: T) : Result<T>()
    data class Failure(val error: AppError) : Result<Nothing>()
}
```

## Extension Functions

Add behavior without inheritance, scoped to where they're used:

```kotlin
fun String.toSlug(): String =
    lowercase().replace(Regex("[^a-z0-9\\\\s-]"), "").replace(Regex("\\\\s+"), "-")
```

## Scope Functions

- `let`: Transform nullable or scoped result
- `apply`: Configure an object
- `also`: Side effects
- Avoid nesting scope functions

## Dependency Injection

Use Koin for DI in Ktor projects:

```kotlin
val appModule = module {
    single<UserRepository> { ExposedUserRepository(get()) }
    single { UserService(get()) }
}
```

## Reference

See skill: `kotlin-patterns` for comprehensive Kotlin patterns including coroutines, DSL builders, and delegation.

---

Source: [Claudary](https://claudary.paisolsolutions.com/skills/kotlin-patterns) · https://claudary.paisolsolutions.com