Ruby 是否支持条件正则表达式
问题描述
只是一个语言功能问题，我知道在正则表达式(或多个正则表达式)之外有很多方法可以做到这一点.
Just a language feature question, I know there's plenty of ways to do this outside of regexes (or with multiple regexes).
ruby 是否支持 条件正则表达式?基本上，正则表达式中的 IF-THEN-ELSE 分支，其中 IF 的谓词是表达式中捕获的组的存在(或不存在).
Does ruby support conditional regular expressions? Basically, an IF-THEN-ELSE branch inside a regular expression, where the predicate for the IF is the presence (or absense) of a captured group in the expression.
在 perl 中，语法是 (?(predicate)yes-pattern|no-pattern) 和
In perl, the syntax is (?(predicate)yes-pattern|no-pattern) as in
/(?:y|(x))(?(1)y|x)/
我无法在我浏览过的任何 ruby 文档中找到任何类似内容的参考，但我想我会在这里询问以确保，以防我搜索错误的单词，或者它已从文档中删除.
I haven't been able to find any reference to anything like it in any ruby docs that I've browsed, but I figured I'd ask here to make sure, in case I was searching for the wrong words, or it was elided from the docs.
解决方案
不，ruby 不支持(1.8 和 1.9 都不支持).
No, ruby does not support that (neither in 1.8 nor 1.9).
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