Compute property arithmetically

Question

In short I am not able to make a computation based on a property within my build file.

Let's say I have:

<property name="basedir" value="${project.basedir}" /> <--Current value 73

How can I know the previous 3 builds (72,71 and 70) OR how can I compute these values(based on the basedir property)?

I have tried (ignore the addition):

1. <property name="basedir" value="${project.basedir}+1" /> <--But it concats the value: 73+1

2. <property name="basedir" value="${project.basedir+1}" /> <--But it is just wrong: build_${env.BUILD_NUMBER+1}

Scenario: Remove old releases (keep some releases in case of a rollback)

P.S: The duplicate link is invalid because this is a deployment via PHING not ANT

Answer 1

You could use an adhoc-task for this:

  <?xml version="1.0"?>
  <project default="main" phingVersion="2.11.0">
  <property name="basedir" value = "73"/>
  <adhoc-task name="increment"><![CDATA[
  class increment extends Task {
      private $value;

      function setvalue($value) {
          $this->value = $value;
      }
     function setProperty($property) {
         $this->property = $property;
      }

     function main() {
         $this->project->setProperty($this->property, ((int) $this->value + 1));
      }
  }
  ]]></adhoc-task>
  <target name="main">
  <echo>${basedir}</echo>
  <increment value="${basedir}" property="basedir"/>
  <echo>${basedir}</echo>
  </target>
  </project>