It is worth to mentioned "modifier spans" like(?i:...). They are more powerful than global flags and modifiers.

I think so, but it's also okay to do that in a separate PR. We can iterate and work incrementally.

The second\b was removed intentionally. It is not needed here.

It is worth also to use possessive qualifiers here.

But it's fine to keep the second\b, and when modifying the example for some other context it might be useful. So I'd be fine with keeping it too. (Note that it's mentioned in the text below also.)

(Also, what's a possessive qualifier?)

Not exactly this example, but see the conversation in#21420 about redundant\b.

This example was fixed in#4443. It was incorrect without\b at the end, but\b between\w and\s is redundant by definition.

Sorry, not "possessive qualifier" but "possessive quantifier" (although in some documents they are named "qualifiers"). A possessive quantifier is a quantifier without backtracking. It is written by adding+ to the quantifier (as non-greed quantifiers are written by adding?). For example, when try to match the pattern with greedy quantifiers\b(\w+)\s+\1\b in "then the", a dumb backtracking engine will try to match "then then", fail, backtrack and try to match consequentially "the ", "th ", "t " until it give up. But with possessive quantifier\b(\w++)\s++\1\b it will not backtrack and fail quicker. It is a new feature in Python 3.11. Even if it is supported in most modern RE engines, it is relatively little known, because it was not initially supported in old RE engines.

Seehttps://www.regular-expressions.info/possessive.html

OK, I've removed the second \b and edited the text below a bit.

I think so, but it's also okay to do that in a separate PR. We can iterate and work incrementally.

But it's fine to keep the second\b, and when modifying the example for some other context it might be useful. So I'd be fine with keeping it too. (Note that it's mentioned in the text below also.)

(Also, what's a possessive qualifier?)