Counter for iteration a list in for task based on math task of ant-contrib

ant-contrib_for_i

<var name="counter" value="0"/>

<for list="{list}" param="{param}">
    <sequential>
        <switch value="${counter}">
            <case value="0">
                <!-- do something -->
            </case>
            <case value="1">
                <!-- do something -->
            </case>
            <!-- other cases -->
        </switch>

        <!-- increase the counter -->
        <math result="counter" 
          operand1="${counter}" 
          operation="+" 
          operand2="1" 
          datatype="int"/>
    </sequential>
</for>

<var name="counter" unset="true"/>