Antlets are designed to be (optionally) downloaded and imported by the importantlet task
sample code
Sample
<?xml version="1.0"?>
<project default="dist" basedir="." name="hello-world">
<description>Helloworld template project.</description>
{{{ <typedef resource="org/apache/ant/antlet/antlib.xml" /> }}}
{{{ <importantlet name="init" href="http://ant.apache.org/antlets" /> }}}
{{{ <target name="dist" > }}}
{{{ <echo message="Build dir is defined in init as ${build.dir}"/> }}}
{{{ </target> }}}
</project>
This will download and automatically import
http://ant.apache.org/antlets/init/xbuild.xml Which looks like
<?xml version="1.0"?>
<project basedir="." name="init.antlet">
<description>Standard Init.</description>
{{{ <property name="build.dir" value="${basedir}/build}" /> }}}
{{{ <mkdir dir="${build.dir}"/> }}}
</project>