Kotlin library that can construct a tree structure

Kotlin library that can construct a tree structure

πŸ• QCompactTreeNode

QCompactTreeNode is a Kotlin library that can construct a tree structure.

  • Just copy and paste QNode.kt into your project
  • You can modify and redistribute it under the MIT License.

How to use



example src code

fun main() {
    // First, you have to create the root node.
    val root = QNode(0)

    val node1 = root add 1
    val node2 = root add 2
    val node3 = node2 add 3
    val node4 = node2 add 4
    val node5 = node4 add 5
    val node6 = node4 add 6
    val node7 = node2 add 7

    val unicodeTree = root.tree(color = QShColor.GREEN, style = QTreeStyle.UNICODE)


    val asciiTree = root.tree(color = QShColor.BLUE, style = QTreeStyle.ASCII)



    val depthFirstResult = root.descendantsList(QSearchAlgo.DepthFirst).toString()

    println("DepthFirst   : $depthFirstResult") // [0, 1, 2, 3, 4, 5, 6, 7]

    val breadthFirstResult = root.descendantsList(QSearchAlgo.BreadthFirst).toString()

    println("BreadthFirst : $breadthFirstResult") // [0, 1, 2, 3, 4, 7, 5, 6]


    // node can store anything
    val rootA = QNode("A")
    val nodeB = rootA add "B"
    val nodeC = nodeB add "C"
    val nodeD = nodeB add "D"
    val nodeE = nodeD add "E"
    val nodeF = nodeE add "F"
    val nodeG = nodeC add "G"

    val textTree = rootA.tree(color = QShColor.CYAN, style = QTreeStyle.UNICODE)


    // You can implement QLazyNode for more complicated situations.
    class QFileNode(override val value: Path) : QLazyNode<Path> {
        override fun hasChildNodeToFill(): Boolean {
            return value.isDirectory()

        override fun fillChildren(): List<QFileNode> = Files.walk(value, 1).filter {
            it != value
        }.map {

        override fun toTreeNodeString(): String {
            return value.name

    val rootDir = Paths.get("rsc-test/root-dir").toAbsolutePath()

    val fileTree = QFileNode(rootDir).fillTree(maxDepth = 2).tree()


Please see QNodeTest.kt for more code examples. This test file is a self-contained, single-file source code that includes a runnable main function. You can easily copy and paste it into your codebase and run it.


Refer to build.gradle.kts to directly check project settings.

dependencies {

How did I create this library

I created this library by developing a program within my own codebase that automatically resolves dependencies at the method or property level, extracts necessary code elements, and generates a compact, self-contained, single-file library.

The program uses PSI to resolve dependencies for function calls and references to classes.

Although my original repository is currently disorganized, I have been gradually extracting and publishing small libraries. I also plan to prepare the original repository for publication in the future


View Github

Leave a Reply

Your email address will not be published. Required fields are marked *