for循环-如何在Ant中生成逗号分隔的列表

Question

如何从Ant中的for循环生成逗号分隔的列表?

我可以使用ant-contrib for循环遍历源属性，但我不确定如何输出到目标属性:

<ac:for list="${comma_seperated}" param="entry">
    <sequential>
         <if>
         <isset property="@{entry}_enabled" />
             <then>
             <!-- append to property enabled_list here -->
             </then>
         </if>
    </sequential>
</ac:for>

Answer 1

使用Ant Addon Flaka遍历csv属性并在每次迭代中添加内容的代码片段:

<project xmlns:fl="antlib:it.haefelinger.flaka">
 <property name="foobar" value="Alpha,Beta,Gamma,Delta,Epsilon,Zeta,Eta,Theta,Iota,Kappa,Lambda"/>
 <property name="foobaz" value="My,Ny,Xi,Omikron,Pi,Rho,Sigma,Tau,Ypsilon,Phi,Chi,Psi,Omega"/>
 <fl:for var="item" in="split('${foobaz}', ',')">
  <fl:let>foobar ::= concat('${foobar}',',#{item}')</fl:let>
 </fl:for>
<echo>$${foobar} => ${foobar}</echo>
</project>

输出:

[echo] ${foobaz} => Alpha,Beta,Gamma,Delta,Epsilon,Zeta,Eta,Theta,Iota,Kappa,Lambda,My,Ny,Xi,Omikron,Pi,Rho,Sigma,Tau,Ypsilon,Phi,Chi,Psi,Omega

EDIT
很高兴你明白了这个想法，尽管我的代码片段有点愚蠢，因为一个人会实现有些结果仅仅是

<property name=someproperty value=${foobar},${foobaz}>

不知道您的需求的细节，但这里有一个改编的片段，添加/length后缀到您的CSV属性的任何项
:

<project xmlns:fl="antlib:it.haefelinger.flaka">
 <property name="foobar" value="Alpha,Beta,Gamma,Delta"/>
 <property name="foobaz" value=""/>
 <fl:for var="item" in="split('${foobar}', ',')">
  <fl:choose>
   <!-- avoid a leading ',' -->
   <fl:when test="'${foobaz}'.length eq 0">
    <fl:let>foobaz ::= concat('${foobaz}','#{item}/length#{item.length}')</fl:let>
   </fl:when>
   <fl:otherwise>
    <fl:let>foobaz ::= concat('${foobaz}',',#{item}/length#{item.length}')</fl:let>
   </fl:otherwise>
  </fl:choose>
 </fl:for>
 <!-- optionally overwrite ${foobar} with ${foobaz} --> 
 <fl:let>foobar ::= '${foobaz}'</fl:let>
 <echo>$${foobar} => ${foobar}</echo>
</project> 

输出:

[echo] ${foobar} => Alpha/length5,Beta/length4,Gamma/length5,Delta/length5

Answer 2

尝试使用标准Ant任务<pathconvert>。参见http://ant.apache.org/manual/Tasks/pathconvert.html。