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Dear Monks,

perlre says this:

(??{ code })

This is a "postponed" regular subexpression. The code is evaluated at run time, at the moment this subexpression may match. **The result of evaluation is considered a regular expression and matched as if it were inserted instead of this construct.**

Then perlre says:

Note that this means that the contents of capture groups defined inside an eval'ed pattern are not available outside of the pattern...

...Thus,

('a' x 100)=~/(??{'(.)' x 100})/

will match, it will not set $1.

Huh? I checked, and in fact $1 is not set. So in my opinion, the last quoted line should say:

Despite the regex insertion, *confoundingly* the capture groups inside this construct are not available after the insertion.

In other words, I don't see how by inserting the resulting regex instead of this construct it follows that the capture groups in the regex won't be available, which perlre seems to think is self-evident.


In reply to Evaluating code in a regex at runtime: (??{...}) by 7stud

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