Kottle

Kotlin language provider for Forge 1.13-1.15. Originally a rewrite of Shadowfacts's Forgelin.

• Shades the Kotlin standard library, runtime, and reflect libraries so you don't have to.
• Provides a Forge IModLanguageProvider for using Kotlin object classes as your main mod class and adds support for object instances for @Mod.EventBusSubscriber
• Currently provides Kotlin libraries with version 1.3.61, Kotlin coroutines version 1.3.2 and JetBrains annotations version 18.0.0.

Usage

First of all, make sure you're on Forge 31.0.0 or higher.

Then, in your build.gradle:

buildscript {
    repositories {
        jcenter()
    }

    dependencies {
        // Remove this line: classpath group: 'net.minecraftforge.gradle', name: 'ForgeGradle', version: '3.+', changing: true
        // trove is forked and used by kotlin and we have to use it instead of the one forked by Forge
        // to avoid compilation errors on Linux (see PR #2)
        classpath(group: 'net.minecraftforge.gradle', name: 'ForgeGradle', version: '3.+', changing: true) {
            exclude group: 'trove', module: 'trove'
        }
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion"
    }
}

apply plugin: 'kotlin'

repositories {
    maven { url 'https://minecraft.curseforge.com/api/maven/' }
}

dependencies {
    implementation "kottle:Kottle:$kottleVersion"
}

, in your gradle.properties:

# This is your kotlin gradle plugin version. For now, use 1.3.61.
kotlinVersion = 1.3.61

# Change this to the most recent release version from CurseForge
kottleVersion = 1.5.2

, in your mods.toml:

modLoader="kotlinfml"
loaderVersion="[1,)"

Finally, replace FMLJavaModLoadingContext references in your code with FMLKotlinModLoadingContext.

For more info, checkout test sources here or my mod, Roomery, here.

FAQ

• addListener(SetupLifecycle::registerItems) crashes the game:

  TL;DR: nothing that can be done about it. Use other methods. See #8