Re^2: Reusing a complex regexp in multiple spots, escaping the regexp

On a tangent, what is the benefit of (?(DEFINE) ...) constructs for repeated patterns here?

Intuitively, I would have opted for interpolating nested $variables holding qr// snippets, especially since I can make them more readable with /x and can unit test them individually.

But I'm curious to learn why you chose this way.

Is it about the handling of capture groups?

I tried to read the relevant docs, but they constantly mention recursion and I can't spot any here...

Cheers Rolf
_{(addicted to the Perl Programming Language :)

see Wikisyntax for the Monastery}

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Re^3: Reusing a complex regexp in multiple spots, escaping the regexp by ikegami (Patriarch) on Apr 14, 2026 at 19:18 UTC
A whole bunch of qr// requires so much more noise. It's far less readable. It's also far less efficient (though perhaps not enough to matter). But you have a point about testability.	[reply]
Re^4: Reusing a complex regexp in multiple spots, escaping the regexp by sleet (Pilgrim) on Apr 15, 2026 at 18:01 UTC
It's also far less efficient (though perhaps not enough to matter). It surprises many people that `qr` is slower than expected: Performance penalty of using qr// It's so perplexing: the qr/ / compiled regex slower than raw string On interpolating stuff into pattern matches	[reply] [d/l]
Re^5: Reusing a complex regexp in multiple spots, escaping the regexp by LanX (Saint) on Apr 15, 2026 at 20:27 UTC
Hmm interesting, and it seems there is no consensus what's happening. Dave_the_m says the qr object is always duplicated because matches depend on scope. Aristotle says, using an additional /o modifier closes the performance gap ... but will alter the semantics Demerphq says he doesn't know what's going on. I think the first and second statement are contradictory or probably hinting at a bug somewhere. Anyway I'm confused, there may be a difference if a `$var= qr/.../` is used directly as a RHS of a match or is interpolated inside a bigger regex. And since it's possible to stringify a qr-object and use the string instead, this adds another layer of confusion. I have to think hard about a concise way to test all of this which wouldn't result in a tl;dr monstrum. Cheers Rolf _{(addicted to the Perl Programming Language :) see Wikisyntax for the Monastery}	[reply] [d/l]
Re^6: Reusing a complex regexp in multiple spots, escaping the regexp by sleet (Pilgrim) on Apr 15, 2026 at 22:32 UTC
Re^7: Reusing a complex regexp in multiple spots, escaping the regexp by LanX (Saint) on Apr 16, 2026 at 12:27 UTC
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Re^4: Reusing a complex regexp in multiple spots, escaping the regexp by LanX (Saint) on Apr 15, 2026 at 09:42 UTC
> A whole bunch of qr// requires so much more noise. It's far less readable I can't follow... I'm sure I could take Hauke's example and translate it 1to1 using 4 variables $INT, $HEX4, $QUOT, $SOMETHING without more lines and any change in readability. I'd even argue it'll become better readable because interpolation is a much more common pattern. And `$INT` is 3 characters shorter than `(?&INT)` Cheers Rolf _{(addicted to the Perl Programming Language :) see Wikisyntax for the Monastery}	[reply] [d/l] [select]


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