First, do you realize (??{ print $^N }) is causing the regexp to try to match "1", the return value of print? You should probably use something that's guaranteed not to match like (??{ print("$^N\n"); '(?!)' })or something that's guaranteed to match like (??{ print("$^N\n"); '(?=)' })

Or if you are only using the contents of the code block for it's side effects, use (?{ ... }) which always succeeds and otherwise has no effect upon the matching process. From perlre

This zero-width assertion evaluates any embedded Perl code. It always succeeds, and its code is not interpolated.
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
Lingua non convalesco, consenesco et abolesco. -- Rule 1 has a caveat! -- Who broke the cabal?
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

In reply to Re^2: Regular Expression Constructs ?<= and ?= by BrowserUk
in thread Regular Expression Constructs ?<= and ?= by eibwen

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