Sample DSL example - Just playing around

sample_dsl.kt

package dev.okano.kotlin.coroutines.mains

data class Header(val name: String, val value: String)

data class HeaderBuilderDsl(val context: Request) {
    companion object {
        fun withContext(context: Request): HeaderBuilderDsl {
            return HeaderBuilderDsl(context)
        }
    }

    infix fun withName(name: String): PartialHeaderWithoutValue {
        return PartialHeaderWithoutValue(context, name)
    }

    data class PartialHeaderWithoutValue(val context: Request, val name: String) {
        infix fun andValue(value: String) {
            context._headers.add(Header(name, value))
        }
    }
}

class Request {
    val header = HeaderBuilderDsl.Companion
    val context = this
    val _headers = mutableListOf<Header>()

    companion object {
        operator fun invoke(init: Request.() -> Unit): Request =
            Request().apply(init)
    }

    operator fun HeaderBuilderDsl.Companion.unaryPlus(): HeaderBuilderDsl {
        return this.withContext(context)
    }

    fun getHeaders() = _headers.toList()
}


fun main(args: Array<String>) {
    val request = Request {
        +header withName "content-type" andValue "application/json"
        +header withName "accept-language" andValue "en_US"
    }

    println(request.getHeaders())
}