tress.kt

gistfile1.txt

package eu.macphail

sealed class PartOfTree
data class Leaf(val sprite: String = "Leaf") : PartOfTree()
data class Flower(val sprite: String = "Flower") : PartOfTree()
data class Branch(val subParts: List<PartOfTree>,
                  val enterBranch: String = "Enter Branch",
                  val exitBranch: String = "Exit Branch") : PartOfTree()

data class Painting(val sprites: String = "") {
    fun add(sprite: String) = if(sprites.isBlank()) {
        Painting(sprite)
    } else {
        Painting("$sprites,$sprite")
    }
}

fun makeBranch(vararg parts: PartOfTree) = Branch(parts.toList())

fun main() {
    val parts = listOf(makeBranch(Leaf(), Flower(), Flower(),
                                        makeBranch(Flower(), Leaf(), Leaf()),
                                        makeBranch(Flower(), Flower(), Flower())),
                                  makeBranch(Flower(), Leaf(), Leaf()),
                                        makeBranch(Leaf(), Leaf(), Flower()),
                                        makeBranch(Flower(), Leaf(), Flower()))
    println(paintTree(parts).sprites)
}

private fun paintTree(parts: List<PartOfTree>, existingPainting: Painting = Painting()): Painting {
    return parts.fold(existingPainting) { painting, part ->
        when (part) {
            is Leaf -> painting.add(part.sprite)
            is Flower -> painting.add(part.sprite)
            is Branch ->
                painting.add(part.enterBranch)
                    .add(paintTree(part.subParts).sprites)
                    .add(part.exitBranch)
        }
    }
}