> One reason (maybe the only reason) that the stringization of a  qr//  object comes wrapped in its own little non-capturing group is so that the further interpolation of something like

> ( examples with appended quantifiers )

Not really.

perlre is actually quite explicit about the why

> > > The caret tells Perl that this cluster doesn't inherit the flags of any surrounding pattern, but uses the system defaults (d-imnsx ), modified by any flags specified.

In other words: It's about preserving the flags of the embedded regex and assuming default if none are specified.

Update demonstration

  DB<7> $U=qr/U/                # always upper case


  DB<8> $i=qr/i${U}i/i          # surrounding case insensitive


  DB<9> p $i
(?^ui:i(?^u:U)i)

  DB<10> p 'iui' =~ $i


  DB<11> p 'iUi' =~ $i
1

  DB<12> p 'IUI' =~ $i
1

  DB<13> p 'IuI' =~ $i


  DB<14> p join "\n", grep { $_ =~ $i } <{i,I}{u,U}{i,I}>
iUi
iUI
IUi
IUI

[download]

Cheers Rolf
(addicted to the Perl Programming Language and ☆☆☆☆ :)
Wikisyntax for the Monastery

In reply to Re^2: Tidying and simplifying a regular expression (flags) by LanX
in thread Tidying and simplifying a regular expression by Dallaylaen

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