如何基于Ant中的限制进行循环 [英] how to do for loop based on a limit in Ant
问题描述
在Ant-contrib中,我们可以执行以下操作:
In Ant-contrib, we can do something like:
<for list="a,b,c,d" param="instence">
但是,如果我没有列表,则只有一个限制,例如limit = 4。
But if I don't have a list, I only have a limit, e.g. limit=4.
是否有一种基于限制的循环方法,例如:
Is there a way to do for loop based on limit, like:
<for limit="4" param="index">
推荐答案
Ant插件 Flaka 为您的问题提供了一些解决方案。
The Ant addon Flaka provides some solutions for your problem.
1)使用while循环
1) Use a while loop
test属性评估一些EL表达式,
可能是一个简单的计数器fe
the test attribute evaluates some EL expression,
which maybe a simple counter, f.e.
<project name="demo" xmlns:fl="antlib:it.haefelinger.flaka">
<!-- some counter -->
<fl:let>
countdown = 3
</fl:let>
<fl:while test=" countdown >= 0 ">
<fl:echo>
#{countdown > 0 ? countdown : 'bang!' }..
</fl:echo>
<fl:let>
countdown = countdown - 1
</fl:let>
</fl:while>
</project>
输出:
[fl:echo] 3..
[fl:echo] 2..
[fl:echo] 1..
[fl:echo] bang!..
或其他表达式,例如检查文件是否存在,意味着循环直到某个文件存在:
or some other expression, f.e. checking for existence of a file, means looping until some file exists :
<fl:while test=" !'/home/rosebud/stop'.tofile.isfile ">
<fl:echo>
still working..
</fl:echo>
</fl:while>
2)使用带有break或continue的for循环:
2) Use a for loop with break or continue :
<project name="demo" xmlns:fl="antlib:it.haefelinger.flaka">
<fl:for var="i" in=" list(1,2,3,4,5,6) ">
<fl:echo>i = #{i}</fl:echo>
<fl:break test=" i == 3 " />
</fl:for>
<fl:for var="i" in=" list(1,2,3,4,5,6) ">
<fl:continue test=" i > 3 " />
<fl:echo>i = #{i}</fl:echo>
</fl:for>
</project>
给出相同的结果:
[fl:echo] i = 1
[fl:echo] i = 2
[fl:echo] i = 3
在 Flaka手册
See more details in the Flaka manual
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