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recursive_regex_for_nested

🔄 Parse Nested Structures with Recursive Patterns​

Oniguruma supports recursive subroutine calls to match arbitrarily nested constructs—ideal for parenthesis, XML tags, or quotes. Define a named subpattern that calls itself with (?&name) inside.

nested = /
  \(
    (?:
      [^()]+      # any non-paren chunk
      | (?&nested)  # recursive call
    )*
  \)
/x

p "((a(b)c)d)".match?(nested)  # => true

You can adapt nested to match HTML-like tags or other paired delimiters by adjusting the outer delimiters.