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views:

97

answers:

2
+4  Q: 

When were non-capturing parentheses added to Perl's regular expressions?

I am having a hard time figuring out the earliest version of perl where non-capturing parentheses are supported in regex patterns?

Can I take this feature for granted for all versions of Perl5?

+4  A: 

Some time before 5.003_07 according to perlre for that version.

eclark  2010-08-08 03:55:05
Thank you. No wonder I could not find it in `perldelta` files.
Sinan Ünür  2010-08-08 04:03:23
+10  A: 

I dug out Perl 5.000 from my archive CDs. It includes

=item (?:regexp)
This groups things like "()" but doesn't make backrefences like "()" does.

So it's in all versions of Perl 5. (It's definitely not in Perl 4 or earlier.)

cjm  2010-08-08 05:13:25
I am impressed and amazed and disturbed that you had an archived CD with Perl 5.000 ;-)
Sinan Ünür  2010-08-08 05:17:13
For extra disturbance, it was the OS/2 port, as that's what I was using back then. :-)
cjm  2010-08-08 05:49:04
FYI, the typo you corrected wasn't mine. In 5.000, `perlre.pod` had "backrefences" in that sentence.
cjm  2010-08-08 06:17:44
@cjm Reinserted the typo for historical accuracy.
Sinan Ünür  2010-08-08 08:00:41
@Sinan: the history isn't secret and is available online http://perldoc.perl.org/index-history.html
Dummy00001  2010-08-09 10:44:48
@Dummy00001 I was not able to locate a mention of when non-capturing parentheses added in any of the deltas, hence the question "Can I take this feature for granted for all versions of Perl5?"
Sinan Ünür  2010-08-09 15:30:23

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