UPD: answered; I was using old perldoc perlre document

Hi,
When I open perldoc perlre, after atomic grouping (?>...), code (?{...}), and some other constructs, it is written:
"WARNING: This extended regular expression feature is considered highly experimental, and may be changed or deleted without notice."
And it seems that these constructs has been known lot of years ago, for example, I find atomic grouping (?>...) in 2002 J.Friedl's book "Mastering Regular Expressions" (II ed.).
So: 1) how long experiments will take on these constructs? 2) is it a good practice to use experimental constructs in book (as J.Friedl used)?..if they are only experimental? 3) what to do for newer programmer if he read that these features are experimental: a) use them? b) wait until there will not be such warnings that feature can be deleted?
And one more question: should I use "given/when" if it is experimental?

In reply to regex experimental constructs: use or not use ? by rsFalse

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