How to create a Dsl in Kotlin?

Mohammad Kallaf Alhjaj
5 min readJul 23
kotlin dsl

What’s A DSL?

A DSL, which stands for Domain-Specific Language, is a programming language or syntax specifically designed and optimized for a particular domain or problem space.

Unlike general-purpose programming languages like Java, Python, or
Kotlin, which are designed to be versatile and handle a wide range of tasks, DSLs are targeted at specific areas and are intended to be more expressive and concise within that domain.

They are particularly valuable in scenarios where the domain is complex and specialized, and a tailored language can greatly enhance productivity and comprehension.

DSLs in Kotlin!

In Kotlin, DSLs (Domain-Specific Languages) are a powerful feature that leverages the language’s flexibility and expressive syntax to create concise and readable code within a specific domain.

Kotlin provides several language features that make it easy to create internal DSLs, which are DSLs defined within the Kotlin language itself.

Kotlin DSLs are commonly used for tasks such as configuration, HTML/XML generation, database querying, and more.

Let’s explore some examples of DSLs in Kotlin:

1. Configuration DSL:

Kotlin DSLs are often used to define configuration files in a more expressive and structured way.

For instance, a simple configuration DSL for an application could look like this:

data class AppConfig(var appName: String = "", var version: String = "", var port: Int = 8080)

fun appConfig(configure: AppConfig.() -> Unit): AppConfig {
val appConfig = AppConfig()
return appConfig

fun main() {
val config = appConfig {
appName = "MyApp"
version = "1.0.0"
port = 8000

println("App Name: ${config.appName}, Version: ${config.version}, Port: ${config.port}")

2. HTML Generation DSL:

You can create a DSL to generate HTML elements in a structured and type-safe manner:

class Tag(val name: String) {
private val children = mutableListOf<Tag>()…
Mohammad Kallaf Alhjaj

Senior Software Engineer, Write about Programming, Technology and Workplace