如何找到下一个不平衡的支撑? [英] How to find the next unbalanced brace?

问题描述

下面的正则表达式捕获了最后一个平衡的 } 之前的所有内容.

The regex below captures everything up to the last balanced }.

现在，什么正则表达式能够捕获下一个不平衡 } 之前的所有内容?换句话说，我怎样才能从 $str 获得 ... {three {four}} Five} 而不是 ... {three {four}} Five}}}?

Now, what regex would be able to capture everything up to the next unbalanced }? In other words, how can I can get ... {three {four}} five} from $str instead of just ... {three {four}}?

my $str = "one two {three {four}} five} six";

if ( $str =~ /
              (
                .*?
                {
                  (?> [^{}] | (?-1) )+
                }
              )
            /sx
   )
   {
     print "$1\n";
   }

推荐答案

所以你要匹配

[noncurlies [block noncurlies [...]]] "}"

block 在哪里

"{" [noncurlies [block noncurlies [...]]] "}"

作为语法:

start    : text "}"
text     : noncurly* ( block noncurly* )*
block    : "{" text "}"
noncurly : /[^{}]/

作为正则表达式 (5.10+):

As a regex (5.10+):

/
   ^
   (
      (
         [^{}]*
         (?:
             \{ (?-1) \}
             [^{}]*
         )*
      )
      \}
   )
/x

作为正则表达式 (5.10+):

As a regex (5.10+):

/
   ^ ( (?&TEXT) \} )

   (?(DEFINE)
      (?<TEXT>   [^{}]* (?: (?&BLOCK) [^{}]* )*   )
      (?<BLOCK>  \{ (?&TEXT) \}                   )
   )
/x

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