Convert Groovy to Kotlin

build.gradle.kts

@@ -0,0 +1,41 @@
+plugins {
+    kotlin("jvm") version "1.9.21"
+    id("org.jetbrains.dokka") version "1.9.10"
+    application
+}
+
+application {
+    mainClass.set("be.amedee.adventofcode.AppKt")
+}
+
+group = "be.amedee"
+version = "1.0-SNAPSHOT"
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation(kotlin("stdlib"))
+    testImplementation("org.jetbrains.kotlin:kotlin-test")
+    testImplementation("io.kotest:kotest-core:4.1.3")
+    testImplementation("io.kotest:kotest-assertions-core:5.6.2")
+    testRuntimeOnly("org.junit.platform:junit-platform-launcher")
+}
+
+tasks.test {
+    useJUnitPlatform()
+    testLogging {
+        events("skipped", "passed", "failed")
+        showStandardStreams = true
+    }
+}
+
+tasks.named("run") {
+    dependsOn(tasks.test)
+    group = "application"
+}
+
+kotlin {
+    jvmToolchain(21)
+}

src/main/kotlin/be/amedee/adventofcode/App.kt

@@ -0,0 +1,8 @@
+package be.amedee.adventofcode
+
+import be.amedee.adventofcode.aoc2015.day01.Day01
+
+fun main() {
+    val day01 = Day01()
+    day01.main()
+}

src/main/kotlin/be/amedee/adventofcode/aoc2015/day01/Day01.kt

@@ -1,40 +1,42 @@
 package be.amedee.adventofcode.aoc2015.day01
 
-fun readStringFromResource(filePath: String) = {}.javaClass.classLoader.getResource(filePath)?.readText()
-
-fun findFloorAndBasementPosition(instructions: String): Pair<Int, Int> {
-    var floor = 0
-    var basementPosition = -1
-
-    for ((index, char) in instructions.withIndex()) {
-        when (char) {
-            '(' -> floor++
-            ')' -> {
-                floor--
-                if (floor == -1 && basementPosition == -1) {
-                    basementPosition = index + 1 // Adjust index to start from 1
-                }
-            }
+/**
+ * Santa is trying to deliver presents in a large apartment building,
+ * but he can't find the right floor - the directions he got are a little confusing.
+ */
+class Day01 {
+
+    /**
+     * Single move to the next floor, up or down.
+     *
+     * @param instruction a single elevator instruction
+     * @return do we go up or down
+     */
+    val move: (String) -> Int = {
+        when (it) {
+            "(" -> 1
+            ")" -> -1
+            else -> 0
         }
     }
 
-    return Pair(floor, basementPosition)
-}
-
-fun main() {
-    // Specify the file path
-    val filePath = "be/amedee/adventofcode/aoc2015/day01/input"
-
-    val puzzleInput: String = readStringFromResource(filePath)!!
-
-    val (floor, basementPosition) = findFloorAndBasementPosition(puzzleInput)
+    /**
+     * The entire list of elevator instructions.
+     *
+     * @param instructions the list of elevator instructions, Lisp-style
+     * @return at which floor Santa ends up
+     */
+    val followInstructions: (String) -> Int = { instructionList ->
+        instructionList
+            .toList()
+            .sumOf { move(it.toString()) }
+    }
 
-    println("Santa ends up on floor $floor.")
+    fun main() {
+        val filePath = "be/amedee/adventofcode/aoc2015/day01/input"
+        val puzzleInput: String = readStringFromResource(filePath)!!
 
-    if (basementPosition != -1) {
-        println("Santa enters the basement at character position $basementPosition.")
-    } else {
-        println("Santa never enters the basement.")
+        val endFloor = followInstructions(puzzleInput)
+        println("Santa ends up on floor $endFloor.")
     }
-
 }

src/main/kotlin/be/amedee/adventofcode/aoc2015/day01/Day01SecondAttempt.kt

@@ -0,0 +1,40 @@
+package be.amedee.adventofcode.aoc2015.day01
+
+fun readStringFromResource(filePath: String) = {}.javaClass.classLoader.getResource(filePath)?.readText()
+
+fun findFloorAndBasementPosition(instructions: String): Pair<Int, Int> {
+    var floor = 0
+    var basementPosition = -1
+
+    for ((index, char) in instructions.withIndex()) {
+        when (char) {
+            '(' -> floor++
+            ')' -> {
+                floor--
+                if (floor == -1 && basementPosition == -1) {
+                    basementPosition = index + 1 // Adjust index to start from 1
+                }
+            }
+        }
+    }
+
+    return Pair(floor, basementPosition)
+}
+
+fun main() {
+    // Specify the file path
+    val filePath = "be/amedee/adventofcode/aoc2015/day01/input"
+
+    val puzzleInput: String = readStringFromResource(filePath)!!
+
+    val (floor, basementPosition) = findFloorAndBasementPosition(puzzleInput)
+
+    println("Santa ends up on floor $floor.")
+
+    if (basementPosition != -1) {
+        println("Santa enters the basement at character position $basementPosition.")
+    } else {
+        println("Santa never enters the basement.")
+    }
+
+}