过滤掉ST4中的空字符串 [英] Filter out empty strings in ST4

问题描述

请考虑以下示例:

<["foo", "", "bar"]; separator=",">

结果如下:

foo,,bar

但是我需要:

foo,bar

在ST4中使用分隔符进行格式化之前，是否有任何方法可以过滤出空字符串值?

Is there any way to filter out empty string values before formating with separator in ST4?

(在真实代码中，值来自另一个模板，该模板具有<if>条件，并为模型中不需要的数据返回空结果，并且我不希望将条件移出该模板以保持模板被封装/隔离)

(In real code the values come from another template, which has <if> condition and returns empty result for undesired data from model, and I don't whant to move the condition out of that template to keep templates incapsulated/isolated.)

推荐答案

我发现有两个辅助功能的解决方法.但这真令人毛骨悚然...

I've found the workaround with two auxilary things. But it is so creepy...

DropEmpty ::= ["": [], default: key]

Separated(l, s, w=false) ::= "<if (DropEmpty.(first(l)))><if (w)><s><endif><first(l)><Separated(rest(l), s, true)><else><if (rest(l))><Separated(rest(l), s, w)><endif><endif>"

MyTemplate() ::= <<
<Separated(["", "foo", "", "bar", "", "", "goo", "", ""], ",")>
>>

这给出了:

foo,bar,goo

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