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 in the Kotlin Compiler archive. Ant version 1.8.2+ is required.

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>

You can also specify the name of the module being compiled as the moduleName attribute:

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 metadata -->
        <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
`libraries`	Paths to Kotlin libraries	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

Passing raw compiler arguments

To pass custom raw compiler arguments, you can use <compilerarg> elements with either value or line attributes. This can be done within the <kotlinc>, <kotlin2js>, and <withKotlin> task elements, as follows:

<kotlinc src="${test.data}/hello.kt" output="${temp}/hello.jar">
    <compilerarg value="-Xno-inline"/>
    <compilerarg line="-Xno-call-assertions -Xno-param-assertions"/>
    <compilerarg value="-Xno-optimize"/>
</kotlinc>

The full list of arguments that can be used is shown when you run kotlinc -help.

Last modified: 11 February 2021