kotlin-html-dsl-tryout

kotlin-html-dsl-tryout

package nl.toefel.kotlin.html.dsl


fun html(init: HTML.() -> Unit): HTML {
    val html = HTML()
    html.init()
    return html
}

interface Element {
    fun render(builder: StringBuilder, indent: String)
}

abstract class Tag(val name: String): Element {
    val children = mutableListOf<Element>()

    protected fun <T : Element> initTag(tag: T, init: T.() -> Unit): T {
        tag.init()
        children.add(tag)
        return tag
    }

    operator fun String.unaryPlus() {
        children.add(TextElement(this))
    }

    override fun render(builder: StringBuilder, indent: String) {
        builder.append("$indent<$name>\n")
        children.forEach {it.render(builder, "$indent    ")}
        builder.append("$indent</$name>\n")
    }

    override fun toString(): String {
        val builder = StringBuilder()
        render(builder, "")
        return builder.toString()
    }
}

class HTML : Tag("html") {
    fun body(init: BODY.() -> Unit): BODY = initTag(BODY(), init)
}

class BODY: Tag("body") {
    fun div(init: DIV.() -> Unit): DIV = initTag(DIV(), init)
    fun a(init: Anchor.() -> Unit): Anchor = initTag(Anchor(), init)
    fun span(init: SPAN.() -> Unit): SPAN = initTag(SPAN(), init)
}
class DIV : Tag("div") {
    fun div(init: DIV.() -> Unit): DIV = initTag(DIV(), init)
    fun a(init: Anchor.() -> Unit): Anchor = initTag(Anchor(), init)
    fun span(init: SPAN.() -> Unit): SPAN = initTag(SPAN(), init)
}
class SPAN : Tag("span") {
    fun div(init: DIV.() -> Unit): DIV = initTag(DIV(), init)
    fun a(init: Anchor.() -> Unit): Anchor = initTag(Anchor(), init)
    fun span(init: SPAN.() -> Unit): SPAN = initTag(SPAN(), init)
}
class Anchor : Tag("anchor") {

}

class TextElement(val text: String) : Element {
    override fun render(builder: StringBuilder, indent: String) {
        builder.append("$indent$text\n")
    }
}

fun main(args: Array<String>) {
    val doc = html {
        body {
            div {
                +"hoi"
                +"sua"
            }
            div {
                a {
                    +"linkje"
                }
            }
            span { +"inside span" }
        }
    }

    println(doc.toString())
}