in reply to Re: Making $ Unicode-aware
in thread Making $ Unicode-aware

From perlrebackslash:

\R is equivalent to (?>\x0D\x0A|\v)

Greetings,
-jo

$gryYup$d0ylprbpriprrYpkJl2xyl~rzg??P~5lp2hyl0p$

Replies are listed 'Best First'.
Re^3: Making $ Unicode-aware
by jcb (Parson) on Jul 28, 2020 at 01:38 UTC

    Is that really intended to only match CRLF or should it be (?>\x0D?\x0A|\v) to also match traditional *nix line endings? (There is still a problem with (?>\x0D?\x0A|\v) — it does not match the traditional CR-only Macintosh line ending.) Why is vertical tab included?

[reply]
[d/l]
[select]

      \v is not the vertical tab. It matches the character class of "vertical whitespace". The characters belonging to this class are listed in perlrecharclass as: 

      LINE FEED
LINE TABULATION
FORM FEED
CARRIAGE RETURN
NEXT LINE
LINE SEPARATOR
PARAGRAPH SEPARATOR

      [download]
      So actually \R matches all single vertical space characters and the two character sequence CR LF. This includes all common line endings.

      Greetings,
      -jo

      $gryYup$d0ylprbpriprrYpkJl2xyl~rzg??P~5lp2hyl0p$
[reply]
[d/l]
[select]

        So \v is a regex class instead of a character escape. That makes sense, then.

        What existing code could changing $ to use \R instead of \n potentially break? Could this raise security issues by widening input validation patterns?

[reply]
[d/l]
[select]

In Section Meditations