Re^12: Reusing a complex regexp in multiple spots, escaping the regexp

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Re^13: Reusing a complex regexp in multiple spots, escaping the regexp by sleet (Pilgrim) on Apr 17, 2026 at 10:02 UTC
The longest explanation of `/o` is in perlfaq6: What is /o really for?.	[reply] [d/l]
Re^14: Reusing a complex regexp in multiple spots, escaping the regexp by LanX (Saint) on Apr 17, 2026 at 11:32 UTC
> The longest explanation of /o This covers exactly my understanding. You'll also find this in perlop for `m//` - "But now, the only reasons to use /o are one of:..." The perldocs are vast and often redundant, and sometimes contradictory. They are like much of the code base a collaborative design. The wording at perlre is at best dubious and as far as I can see not substationated. As long as nobody shows me a real bug caused by /o I'd call this BS. Cheers Rolf _{(addicted to the Perl Programming Language :) see Wikisyntax for the Monastery}	[reply]
Re^15: Reusing a complex regexp in multiple spots, escaping the regexp by dave_the_m (Monsignor) on Apr 17, 2026 at 11:52 UTC
Well for example, consider the following code: `for my $i (1..2) { print "match\n" if "x1" =~ /x${print "doing arg\n"; \1}/o; }` [download] On threaded perls it prints "doing arg" twice; on unthreaded, once. Dave.	[reply] [d/l]
Re^16: Reusing a complex regexp in multiple spots, escaping the regexp by LanX (Saint) on Apr 17, 2026 at 13:59 UTC
Re^17: Reusing a complex regexp in multiple spots, escaping the regexp by dave_the_m (Monsignor) on Apr 17, 2026 at 14:52 UTC
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Re^16: Reusing a complex regexp in multiple spots, escaping the regexp by LanX (Saint) on Apr 17, 2026 at 13:27 UTC
Re^17: Reusing a complex regexp in multiple spots, escaping the regexp by choroba (Cardinal) on Apr 17, 2026 at 13:30 UTC
Re^13: Reusing a complex regexp in multiple spots, escaping the regexp by LanX (Saint) on Apr 17, 2026 at 11:36 UTC
I did some research and couldn't find a bug introduced by /o. Please demonstrate one, which is not just someone complaining that it acts differently, or misunderstood the o for optimize instead of once. It's like complaining about `state` being buggy since it acts differently to `my` ... Cheers Rolf _{(addicted to the Perl Programming Language :) see Wikisyntax for the Monastery}	[reply]
Re^14: Reusing a complex regexp in multiple spots, escaping the regexp by tobyink (Canon) on Apr 17, 2026 at 14:03 UTC
It's like complaining about state being buggy since it acts differently to my ... Indeed, that's exactly what it is. Why it could be considered buggy in the case of "/o" though is that it's poorly documented, rarely desired, and very easy to miss when debugging because it's a single character often hidden away in the middle of or at the end of an expression, instead of a full keyword at the start of statement like `state`. Hire me at Toby Ink Ltd or Join my OnlyFans	[reply] [d/l]
Re^15: Reusing a complex regexp in multiple spots, escaping the regexp by LanX (Saint) on Apr 17, 2026 at 14:11 UTC
The poor and distributedš documentation is the problem And the way perldocs are often handled as witty prose resulting from group dynamics instead of being based on evidence (i.e. test cases). I don't think it's ever appropriate to flag a feature "buggy" if there are unexpected side-effects a "warning" should be explained in a footnote. if they are really "buggy", they should be disabled. Cheers Rolf _{(addicted to the Perl Programming Language :) see Wikisyntax for the Monastery} š) `perlop` has far more than `perlre` and `perlretut` has only a "\o ... beyond the scope of this introduction" ...	[reply]