Ant substring by position - ant

Question

I need to extract a substring from property value by length, f.e. :
<property name="prop1" value="nameBLABLABLA" />
I want get the value
name
Is it possible without using javascript code ?

Answer 1

Not with vanilla ant, you would need to add some Ant addon like Antcontrib (latest release 2006 !) or Ant Flaka - means you'll need additional jars/libraries.
With using the jdk builtin Javascript engine it's as easy as :
<project>
<!-- create a macrodef for reuse -->
<macrodef name="getsubstring">
<attribute name="src"/>
<attribute name="from"/>
<attribute name="to"/>
<attribute name="result"/>
<sequential>
<script language="javascript">
project.setProperty(
"#{result}", "#{src}".substring(#{from},#{to})
);
</script>
</sequential>
</macrodef>
<property name="foo" value="nameBLABLABLA"/>
<getsubstring src="${foo}" from="0" to="4" result="foobar"/>
<echo> $${foobar} => ${foobar}</echo>
</project>
No additional libraries needed.
Created a macrodef that works for properties respectively for strings in general.
The JavaScript engine understands Javascript and Java and you'll get full access to Ant api.

Answer 2

I'd use JavaScript as in Rebse's answer, but there is a way to do this without it using <loadresource> and a <tokenfilter>. This uses start/length rather than from/to for the substring:
<macrodef name="getsubstring">
<attribute name="src"/>
<attribute name="start"/>
<attribute name="length"/>
<attribute name="result"/>
<sequential>
<loadresource property="#{result}">
<string value="#{src}}" />
<filterchain>
<tokenfilter>
<replaceregex pattern="^.{#{start}}(.{#{length}}).*" replace="\1" />
</tokenfilter>
</filterchain>
</loadresource>
</sequential>
</macrodef>
<property name="prop1" value="nameBLABLABLA" />
<getsubstring src="${prop1}" start="0" length="4" result="p"/>
<echo message="${p}" />