That is true. I can see no good way to avoid that, either. Something like:
my $coderef = eval "BEGIN{goto skip;}sub { $code } BEGIN{skip: print '
+Skipped!'}";
will not work. Not that I am sure it would be good if it did either... return and exit both also yield unsatisfying results, not surprisingly.
However, if you are afraid that someone might execute harmful code, then that is a whole nother issue, and you will not be protected just by verifying the syntax (which was what I addressed). However, if you use Safe, and do like this:
use Safe;
my $compartment = new Safe;
my $coderef = $compartment->reval("sub{$code}") or die "$@";
$coderef->(); # execute the code
The Safe compartment will stop whatever you decide is harmful code even in BEGIN blocks.
If the issue rather is that it is annoying that code will become executed, well then some kind of filter might be in place I guess. For instance, for nearly all applications I could think of (short of a perl editor of course) disallowing the word "BEGIN" in the input (possibly in special cases, like followed by braces) would not be a big problem, would it?
It is definetely something to be aware of though. Good call. :)
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