Kotlin support

.classpath

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-11/"/>
+	<classpathentry kind="con" path="org.eclipse.buildship.core.gradleclasspathcontainer"/>
+	<classpathentry kind="output" path="bin/default"/>
+</classpath>

.project

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>lingua-franca</name>
+	<comment>Project lingua-franca created by Buildship.</comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+		<buildCommand>
+			<name>org.eclipse.buildship.core.gradleprojectbuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.eclipse.jdt.core.javanature</nature>
+		<nature>org.eclipse.buildship.core.gradleprojectnature</nature>
+	</natures>
+</projectDescription>

build.gradle

@@ -1,14 +1,16 @@
 buildscript {
+	ext.kotlinVersion = "1.4.10" // sync with pom.xml
 	repositories {
 		mavenCentral()
 	}
 	dependencies {
 		classpath 'org.xtext:xtext-gradle-plugin:2.0.8'
+		classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlinVersion"
 	}
 }
 
 plugins {
-    id "com.github.johnrengelman.shadow" version "6.0.0"
+	id 'com.github.johnrengelman.shadow' version '6.0.0'
 	id 'java'
 	id 'jacoco'
 }
@@ -19,19 +21,34 @@ subprojects {
 		mavenCentral()
 	}
 
-	apply plugin: 'java'
+	apply plugin: 'kotlin'
+	compileKotlin {
+		destinationDir = compileJava.destinationDir
+		kotlinOptions {
+			jvmTarget = "1.8"
+		}
+	}
+
 	dependencies {
 		implementation platform("org.eclipse.xtext:xtext-dev-bom:${xtextVersion}")
 		// https://mvnrepository.com/artifact/com.google.inject/guice
 		implementation group: 'com.google.inject', name: 'guice', version: '5.0.1'
 		// https://mvnrepository.com/artifact/commons-cli/commons-cli
 		implementation group: 'commons-cli', name: 'commons-cli', version: '1.4'
-	}
+    }
+    dependencies {
+        implementation group: 'org.jetbrains.kotlin', name: 'kotlin-stdlib', version: kotlinVersion
+        implementation group: 'org.jetbrains.kotlin', name: 'kotlin-reflect', version: kotlinVersion
+    }
+
 
 	apply plugin: 'org.xtext.xtend'
 	apply from: "${rootDir}/gradle/source-layout.gradle"
 	apply plugin: 'eclipse'
-
+
+	// generate xtend sources before kotlin compilation
+	compileKotlin.dependsOn("generateXtext")
+
 	group = 'org.lflang'
 	version = '0.1.0-SNAPSHOT'
 
@@ -41,4 +58,11 @@ subprojects {
 	configurations.all {
 		exclude group: 'asm'
 	}
+
+	// Delete generated sources on `gradle clean`
+	clean.doFirst {
+		project.logger.info("Deleting ${projectDir}/xtend-gen, src-gen")
+		delete "${projectDir}/xtend-gen/"
+		delete "${projectDir}/src-gen/"
+	}
 }

example/.gitignore

@@ -6,4 +6,6 @@
 /*/test-bin/
 /*/src-gen/
 my_trace
-
+include
+lib
+share

gradle/source-layout.gradle

@@ -2,10 +2,12 @@ if (name.endsWith(".tests")) {
 	sourceSets {
 		main {
 			java.srcDirs = []
+			kotlin.srcDirs = []
 			resources.srcDirs = []
 		}
 		test {
 			java.srcDirs = ['src', 'src-gen']
+			kotlin.srcDirs = ['src', 'src-gen']
 			resources.srcDirs = ['src', 'src-gen']
 			xtendOutputDir = 'xtend-gen'
 		}
@@ -14,6 +16,7 @@ if (name.endsWith(".tests")) {
 	sourceSets {
 		main {
 			java.srcDirs = ['src', 'src-gen']
+			kotlin.srcDirs = ['src', 'src-gen', 'xtend-gen']
 			resources.srcDirs = ['src', 'src-gen']
 			xtendOutputDir = 'xtend-gen'
 		}

oomph/LinguaFranca.setup

@@ -166,6 +166,24 @@
         url="http://download.eclipse.org/modeling/tmf/xtext/updates/composite/releases/"/>
     <description>Install the tools needed in the IDE to work with the source code for ${scope.project.label}</description>
   </setupTask>
+  <setupTask
+      xsi:type="setup.p2:P2Task">
+    <requirement
+        name="202103162301.org.eclipse.ajdt"/>
+    <requirement
+        name="202103162301.org.eclipse.ajdt.other"/>
+    <repository
+        url="http://download.eclipse.org/tools/ajdt/410/dev/update"/>
+  </setupTask>
+  <setupTask
+      xsi:type="setup.p2:P2Task">
+    <requirement
+        name="org.jetbrains.kotlin.feature.feature.group"/>
+    <requirement
+        name="org.jetbrains.kotlin.gradle.feature.feature.group"/>
+    <repository
+        url="https://download.jetbrains.com/kotlin/eclipse-plugin/last"/>
+  </setupTask>
   <setupTask
       xsi:type="setup:VariableTask"
       name="git.clone.lingua.franca.branch"
@@ -332,6 +350,8 @@
             versionRange="2.25.0"/>
         <requirement
             name="org.eclipse.platform.source.feature.group"/>
+        <requirement
+            name="org.jetbrains.kotlin.feature.feature.group"/>
         <requirement
             name="org.eclipse.emf.mwe2.launcher.feature.group"/>
         <requirement
@@ -378,6 +398,8 @@
               url="https://www.pydev.org/updates/"/>
           <repository
               url="http://download.eclipse.org/wildwebdeveloper/releases/latest/"/>
+          <repository
+              url="https://download.jetbrains.com/kotlin/eclipse-plugin/last"/>
         </repositoryList>
       </targlet>
     </setupTask>

org.lflang.diagram/pom.xml

@@ -32,6 +32,10 @@
 				<groupId>org.eclipse.xtend</groupId>
 				<artifactId>xtend-maven-plugin</artifactId>
 			</plugin>
+			<plugin>
+				<groupId>org.jetbrains.kotlin</groupId>
+				<artifactId>kotlin-maven-plugin</artifactId>
+			</plugin>
 		</plugins>
 	</build>
 </project>