c# – 如何进行平衡组捕获？

因此,必须有一些方法来捕获而不是消费,显而易见的方法是使用积极的前瞻.从那里,你可以把你使用的表达,尽管有一些变化,以适应新的焦点变化,我想出：

(?=([A-Z](?:(?:(?'O'{)[^{}]*)+(?:(?'-O'})[^{}]*?)+)+(?(O)(?!))))

[我还将’打开’重命名为’O’并删除了用于近距离大括号的命名捕获,以缩短并避免在比赛中产生噪音]

在regexhero.net(我目前唯一知道的免费.NET正则表达式测试程序)中,我得到了以下捕获组：

1: R{R{abc}aD{mnoR{xyz}}}
1: R{abc}
1: D{mnoR{xyz}}
1: R{xyz}

正则表达式的细分：

(?=                         # Opening positive lookahead
    ([A-Z]                  # Opening capture group and any uppercase letter (to match R & D)
        (?:                 # First non-capture group opening
            (?:             # Second non-capture group opening
                (?'O'{)     # Get the named opening brace
                [^{}]*      # Any non-brace
            )+              # Close of second non-capture group and repeat over as many times as necessary
            (?:             # Third non-capture group opening
                (?'-O'})    # Removal of named opening brace when encountered
                [^{}]*?     # Any other non-brace characters in case there are more nested braces
            )+              # Close of third non-capture group and repeat over as many times as necessary
        )+                  # Close of first non-capture group and repeat as many times as necessary for multiple side by side nested braces
        (?(O)(?!))          # Condition to prevent unbalanced braces
    )                       # Close capture group
)                           # Close positive lookahead

以下内容在C#中不起作用

我实际上想要尝试它应该如何在PCRE引擎上运行,因为有选项可以使用递归正则表达式,我认为它更容易,因为我更熟悉它并且产生了更短的正则表达式:)

(?=([A-Z]{(?:[^{}]|(?1))+}))

regex101 demo

(?=                    # Opening positive lookahead
    ([A-Z]             # Opening capture group and any uppercase letter (to match R & D)
        {              # Opening brace
            (?:        # Opening non-capture group
                [^{}]  # Matches non braces
            |          # OR
                (?1)   # Recurse first capture group
            )+         # Close non-capture group and repeat as many times as necessary
        }              # Closing brace
    )                  # Close of capture group
)                      # Close of positive lookahead