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Using Ant

Getting the Ant Tasks

Kotlin provides three tasks for Ant:

  • kotlinc: Kotlin compiler targeting the JVM
  • kotlin2js: Kotlin compiler targeting JavaScript
  • withKotlin: Task to compile Kotlin files when using the standard javac Ant task

These tasks are defined in the kotlin-ant.jar library which is located in the lib folder for the Kotlin Compiler

Targeting JVM with Kotlin-only source

When the project consists of exclusively Kotlin source code, the easiest way to compile the project is to use the kotlinc task

<project name="Ant Task Test" default="build">
    <typedef resource="org/jetbrains/kotlin/ant/antlib.xml" classpath="${kotlin.lib}/kotlin-ant.jar"/>

    <target name="build">
        <kotlinc src="hello.kt" output="hello.jar"/>
    </target>
</project>

where ${kotlin.lib} points to the folder where the Kotlin standalone compiler was unzipped.

Targeting JVM with Kotlin-only source and multiple roots

If a project consists of multiple source roots, use src as elements to define paths

<project name="Ant Task Test" default="build">
    <typedef resource="org/jetbrains/kotlin/ant/antlib.xml" classpath="${kotlin.lib}/kotlin-ant.jar"/>

    <target name="build">
        <kotlinc output="hello.jar">
            <src path="root1"/>
            <src path="root2"/>
        </kotlinc>
    </target>
</project>

Targeting JVM with Kotlin and Java source

If a project consists of both Kotlin and Java source code, while it is possible to use kotlinc, to avoid repetition of task parameters, it is recommended to use withKotlin task

<project name="Ant Task Test" default="build">
    <typedef resource="org/jetbrains/kotlin/ant/antlib.xml" classpath="${kotlin.lib}/kotlin-ant.jar"/>

    <target name="build">
        <delete dir="classes" failonerror="false"/>
        <mkdir dir="classes"/>
        <javac destdir="classes" includeAntRuntime="false" srcdir="src">
            <withKotlin/>
        </javac>
        <jar destfile="hello.jar">
            <fileset dir="classes"/>
        </jar>
    </target>
</project>

To specify additional command line arguments for <withKotlin>, you can use a nested <compilerArg> parameter. The full list of arguments that can be used is shown when you run kotlinc -help. You can also specify the name of the module being compiled as the moduleName attribute:

<withKotlin moduleName="myModule">
    <compilerarg value="-no-stdlib"/>
</withKotlin>

Targeting JavaScript with single source folder

<project name="Ant Task Test" default="build">
    <typedef resource="org/jetbrains/kotlin/ant/antlib.xml" classpath="${kotlin.lib}/kotlin-ant.jar"/>

    <target name="build">
        <kotlin2js src="root1" output="out.js"/>
    </target>
</project>

Targeting JavaScript with Prefix, PostFix and sourcemap options

<project name="Ant Task Test" default="build">
    <taskdef resource="org/jetbrains/kotlin/ant/antlib.xml" classpath="${kotlin.lib}/kotlin-ant.jar"/>

    <target name="build">
        <kotlin2js src="root1" output="out.js" outputPrefix="prefix" outputPostfix="postfix" sourcemap="true"/>
    </target>
</project>

Targeting JavaScript with single source folder and metaInfo option

The metaInfo option is useful, if you want to distribute the result of translation as a Kotlin/JavaScript library. If metaInfo was set to true, then during compilation additional JS file with binary metadata will be created. This file should be distributed together with the result of translation.

<project name="Ant Task Test" default="build">
    <typedef resource="org/jetbrains/kotlin/ant/antlib.xml" classpath="${kotlin.lib}/kotlin-ant.jar"/>

    <target name="build">
        <!-- out.meta.js will be created, which contains binary descriptors -->
        <kotlin2js src="root1" output="out.js" metaInfo="true"/>
    </target>
</project>

References

Complete list of elements and attributes are listed below

Attributes common for kotlinc and kotlin2js

Name Description Required Default Value
src Kotlin source file or directory to compile Yes  
nowarn Suppresses all compilation warnings No false
noStdlib Does not include the Kotlin standard library into the classpath No false
failOnError Fails the build if errors are detected during the compilation No true

kotlinc Attributes

Name Description Required Default Value
output Destination directory or .jar file name Yes  
classpath Compilation class path No  
classpathref Compilation class path reference No  
includeRuntime If output is a .jar file, whether Kotlin runtime library is included in the jar No true
moduleName Name of the module being compiled No The name of the target (if specified) or the project

kotlin2js Attributes

Name Description Required
output Destination file Yes
library Library files (kt, dir, jar) No
outputPrefix Prefix to use for generated JavaScript files No
outputSuffix Suffix to use for generated JavaScript files No
sourcemap Whether sourcemap file should be generated No
metaInfo Whether metadata file with binary descriptors should be generated No
main Should compiler generated code call the main function No