I can think of many uses for non-capturing parentheses with repetition. In fact, non-capturing parentheses with repetition are more sane than capturing parentheses with repetition, because the capturing parentheses will only keep the last match of the repetition. As an example a simple checker to check that a line matches a CSV-like format, using non-capturing parentheses and repetition:

$line =~ /^(?:[^,]+|"[^"]+")(?:,(?:[^,]+|"[^"]+"))*$/

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That one matches one well-formed column, and then optionally a repetition of comma and more well-formed column.

In reply to Re^5: regex extraction for variable number of args by Corion
in thread regex extraction for variable number of args by NetWallah

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