The following sentance appears in perlre in reference to the (?{...}) and (??{...}) 

...the rules to determine where the code ends are somewhat convoluted.

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anyone care to try for an explanation of what this means exactly (or even roughly)?

Examine what is said, not who speaks.
1) When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.
2) The only way of discovering the limits of the possible is to venture a little way past them into the impossible
3) Any sufficiently advanced technology is indistinguishable from magic.
Arthur C. Clarke.

In reply to Perlre interpretation required by BrowserUk

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