arc:check

<arc:set attr="result.number" value="95" />

<!-- Check that the number attribute exists on the result item first. -->
<arc:check attr="result.number">
  <!-- If true, add a header. -->
  <arc:if exp="[result.number | lessthan(100)]">
    <arc:set attr="out.header:numberlessthan100" value="true" />
    <arc:set attr="out.filepath" value="[filepath]" />
    <arc:push item="out" />
    <!-- Else, throw an error. -->
    <arc:else>
      <arc:throw code="HighValue" desc="The target value was above the desired value of 100." />
    </arc:else>
  </arc:if>
</arc:check>

<arc:enum range="1..10">
  <!-- Check the current iteration and break if it is equal to 5. -->
  <arc:check value="[_value | equals(5)]" action="break" />
  <!-- For iterations not equal to 5, create a file and push it as output. -->
  <arc:setm item="out">
    FileName=Result_[_value].txt
    Data=The enumeration value is [_value].
  </arc:setm>
  <arc:push item="out" />
</arc:enum>