everything-claude-code / rules

---
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.

More agent context in tpavanipradeep/everything-claude-code

81 other files this repository gives its agents, the first 60 shown.

Also found in 16 other repositories

The same file, byte for byte, in the weekly crawl of public GitHub; the 10 with the most stars.

• affaan-m/ECC246k
• loulanyue/awesome-claude-notes272
• mturac/everything-openai-codex89
• mit-network/everything-claude-code76
• Fmarzochi/EGC52
• ysyecust/everything-claude-code44
• yapota2018/affaan-m-everything-claude-code4
• ArogyaReddy/https-github.com-affaan-m-everything-claude-code12
• divenhuang88/everything-claude-code1
• elainesmithburkel-code/everything-claude-code1