You will have to prevent the (?{code}) construct from finding its way into your user's input, lest they manage to inject some unsavory tidbit into your system.
That's not more complicated than not typing use re 'eval';. That is, by default, Perl doesn't honour (?{code}) constructs in interpolated code.

In reply to Re^2: Validating Regular Expression by JavaFan
in thread Validating Regular Expression by Anonymous Monk

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