🎯 KotlinScript

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Write Kotlin, Execute JavaScript

Part of the CapybaraScript Company 🦫

English

🎯 Kotlin syntax that runs on Node.js. No JVM required!

KotlinScript is a transpiler that converts Kotlin-like syntax into JavaScript, allowing you to write code with Kotlin's modern syntax while leveraging the entire Node.js ecosystem.

✨ Features

• 🎯 Kotlin syntax - Write code that looks and feels like Kotlin
• ⚡ Runs on Node.js - No JVM or Kotlin compiler needed
• 🔄 Real-time transpilation - Converts your code on the fly
• 📦 Easy to use - Simple CLI interface
• 🎨 Beautiful error messages - Clear and helpful error reporting
• 🦫 By CapybaraScript - Open source language distribution

🚀 Installation

npm install -g kotlinscript

Or use it locally:

npm install kotlinscript

📖 Quick Start

Command Line:

# Run a KotlinScript file
kotlinscript myfile.kt

# Or use the short alias
kt myfile.kt

Programmatic:

const KotlinScript = require('kotlinscript');
const code = 'println("Hello from Kotlin!")';
KotlinScript.run(code);

🎓 Syntax Guide

Print/Output:

println("Hello, World!")
print("No newline")
println("Value: $value")

Variables:

val name = "Kotlin"  // immutable
var age = 5          // mutable
val active: Boolean = true
val nothing: String? = null

Functions:

fun greet(name: String) {
    println("Hello, $name!")
}

fun add(a: Int, b: Int): Int {
    return a + b
}

// Single expression
fun multiply(a: Int, b: Int) = a * b

val result = add(5, 3)
greet("Developer")

String Templates:

val name = "Kotlin"
println("Hello, $name!")
println("2 + 2 = ${2 + 2}")
println("Length: ${name.length}")

Conditionals:

val max = if (a > b) a else b

when (x) {
    1 -> println("One")
    2 -> println("Two")
    else -> println("Other")
}

if (age > 18) {
    println("Adult")
} else if (age > 13) {
    println("Teen")
} else {
    println("Child")
}

Loops:

// Range
for (i in 1..5) {
    println(i)
}

// Until (exclusive)
for (i in 0 until 10) {
    println(i)
}

// Step
for (i in 0..10 step 2) {
    println(i)
}

// Collection
val fruits = listOf("apple", "banana")
for (fruit in fruits) {
    println(fruit)
}

// While
var count = 0
while (count < 5) {
    println(count)
    count++
}

Collections:

// List
val fruits = listOf("apple", "banana", "orange")
val mutableList = mutableListOf(1, 2, 3)
mutableList.add(4)

println(fruits[0])
println(fruits.size)

// Map
val person = mapOf(
    "name" to "Alice",
    "age" to 30
)

println(person["name"])

// Mutable Map
val mutableMap = mutableMapOf<String, Int>()
mutableMap["key"] = 42

Data Classes:

data class Person(val name: String, val age: Int) {
    fun greet() {
        println("Hi, I'm $name")
    }
}

val p = Person("Alice", 30)
p.greet()
println(p.name)

Classes:

class Person(val name: String, var age: Int) {
    fun greet() {
        println("Hi, I'm $name, $age years old")
    }
    
    fun birthday() {
        age++
    }
}

val p = Person("Bob", 25)
p.greet()
p.birthday()

Lambda Functions:

val numbers = listOf(1, 2, 3, 4, 5)

numbers.forEach { num ->
    println(num)
}

val doubled = numbers.map { it * 2 }
val evens = numbers.filter { it % 2 == 0 }

val sum = numbers.reduce { acc, num -> acc + num }

Null Safety:

var name: String? = null
println(name?.length)  // Safe call
println(name ?: "Default")  // Elvis operator

val length = name?.length ?: 0

Extension Functions:

fun String.shout(): String {
    return this.uppercase() + "!"
}

println("hello".shout())  // "HELLO!"

Try/Catch:

try {
    riskyOperation()
} catch (e: Exception) {
    println("Error: ${e.message}")
} finally {
    println("Cleanup")
}

Imports:

import "fs"
import "path" as pathModule

val content = fs.readFileSync("file.txt", "utf8")

🎯 Complete Examples

Fibonacci:

fun fibonacci(n: Int): Int {
    return if (n <= 1) n else fibonacci(n - 1) + fibonacci(n - 2)
}

fun main() {
    for (i in 0..10) {
        println("Fib($i) = ${fibonacci(i)}")
    }
}

main()

Person Manager:

data class Person(val name: String, var age: Int) {
    fun greet() = println("Hi, I'm $name")
    fun haveBirthday() { age++ }
}

fun main() {
    val people = mutableListOf(
        Person("Alice", 30),
        Person("Bob", 25),
        Person("Charlie", 35)
    )
    
    people.forEach { it.greet() }
    
    val adults = people.filter { it.age >= 30 }
    println("Adults: ${adults.size}")
    
    people.forEach { it.haveBirthday() }
    println("After birthdays:")
    people.forEach { 
        println("${it.name} is now ${it.age}")
    }
}

main()

Simple Web Server:

import "http"

fun handleRequest(req: Any, res: Any) {
    res.writeHead(200, mapOf("Content-Type" to "text/plain"))
    res.end("Hello from KotlinScript!")
}

fun main() {
    val server = http.createServer(::handleRequest)
    server.listen(3000)
    println("🎯 Server running on port 3000")
}

main()

Number Processing:

fun main() {
    val numbers = listOf(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
    
    println("Original: $numbers")
    
    val doubled = numbers.map { it * 2 }
    println("Doubled: $doubled")
    
    val evens = numbers.filter { it % 2 == 0 }
    println("Evens: $evens")
    
    val sum = numbers.reduce { acc, n -> acc + n }
    println("Sum: $sum")
    
    val bigNumbers = numbers.filter { it > 5 }
                            .map { it * 3 }
    println("Big numbers tripled: $bigNumbers")
}

main()

🔧 How It Works

KotlinScript transpiles Kotlin-like syntax to JavaScript:

1. Parses Kotlin-style code
2. Converts to equivalent JavaScript
3. Executes in Node.js runtime

💡 Why KotlinScript?

• Learn Kotlin syntax while using Node.js ecosystem
• Android developers can use familiar syntax in backend
• Modern features like data classes, lambdas, null safety
• No JVM needed - runs directly on Node.js
• Part of CapybaraScript family 🦫

📧 Contact

• Company: CapybaraScript 🦫
• Author: capybarascript
• Email: [email protected]
• npm: npmjs.com/package/kotlinscript

📝 License

MIT License - Free to use in your projects!

Português

🎯 Sintaxe Kotlin rodando no Node.js. Sem necessidade de JVM!

KotlinScript é um transpilador que converte sintaxe estilo Kotlin em JavaScript, permitindo que você escreva código com a sintaxe moderna do Kotlin enquanto aproveita todo o ecossistema do Node.js.

✨ Recursos

• 🎯 Sintaxe Kotlin - Escreva código que parece e funciona como Kotlin
• ⚡ Roda no Node.js - Sem necessidade de JVM ou compilador Kotlin
• 🔄 Transpilação em tempo real - Converte seu código na hora
• 📦 Fácil de usar - Interface CLI simples
• 🎨 Mensagens de erro bonitas - Relatórios claros e úteis
• 🦫 Por CapybaraScript - Distribuição open source de linguagens

🚀 Instalação

npm install -g kotlinscript

Ou use localmente:

npm install kotlinscript

📖 Começando

Linha de comando:

# Execute um arquivo KotlinScript
kotlinscript meuarquivo.kt

# Ou use o alias curto
kt meuarquivo.kt

Programático:

const KotlinScript = require('kotlinscript');
const codigo = 'println("Olá do Kotlin!")';
KotlinScript.run(codigo);

🎓 Guia de Sintaxe

Print/Saída:

println("Olá, Mundo!")
print("Sem quebra de linha")
println("Valor: $valor")

Variáveis:

val nome = "Kotlin"  // imutável
var idade = 5        // mutável
val ativo: Boolean = true
val nada: String? = null

Funções:

fun saudar(nome: String) {
    println("Olá, $nome!")
}

fun somar(a: Int, b: Int): Int {
    return a + b
}

// Expressão única
fun multiplicar(a: Int, b: Int) = a * b

val resultado = somar(5, 3)
saudar("Desenvolvedor")

Coleções:

// Lista
val frutas = listOf("maçã", "banana", "laranja")
val listaEditavel = mutableListOf(1, 2, 3)
listaEditavel.add(4)

println(frutas[0])
println(frutas.size)

// Mapa
val pessoa = mapOf(
    "nome" to "Alice",
    "idade" to 30
)

Data Classes:

data class Pessoa(val nome: String, val idade: Int) {
    fun saudar() {
        println("Oi, eu sou $nome")
    }
}

val p = Pessoa("Alice", 30)
p.saudar()

Lambdas:

val numeros = listOf(1, 2, 3, 4, 5)

numeros.forEach { num ->
    println(num)
}

val dobrados = numeros.map { it * 2 }
val pares = numeros.filter { it % 2 == 0 }

🎯 Exemplos Completos

Fibonacci:

fun fibonacci(n: Int): Int {
    return if (n <= 1) n else fibonacci(n - 1) + fibonacci(n - 2)
}

fun main() {
    for (i in 0..10) {
        println("Fib($i) = ${fibonacci(i)}")
    }
}

main()

Processamento de Números:

fun main() {
    val numeros = listOf(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
    
    println("Original: $numeros")
    
    val dobrados = numeros.map { it * 2 }
    println("Dobrados: $dobrados")
    
    val pares = numeros.filter { it % 2 == 0 }
    println("Pares: $pares")
    
    val soma = numeros.reduce { acc, n -> acc + n }
    println("Soma: $soma")
}

main()

🔧 Como Funciona

KotlinScript transpila sintaxe Kotlin para JavaScript:

1. Analisa código estilo Kotlin
2. Converte para JavaScript equivalente
3. Executa no runtime do Node.js

💡 Por Que KotlinScript?

• Aprenda sintaxe Kotlin usando ecossistema Node.js
• Desenvolvedores Android podem usar sintaxe familiar no backend
• Recursos modernos como data classes, lambdas, null safety
• Sem JVM - roda direto no Node.js
• Parte da família CapybaraScript 🦫

📧 Contato

• Empresa: CapybaraScript 🦫
• Autor: capybarascript
• Email: [email protected]
• npm: npmjs.com/package/kotlinscript

📝 Licença

Licença MIT - Livre para usar nos seus projetos!

Made with 💙 by CapybaraScript Company 🦫

Part of the open source language distribution family