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Postings from September 2001
Says Dave Mitchell:
> Closures ... can also be dangerous and counter-intuitive, espcially to
> the uninitiated. For example, how many people could say what the
> following should output, with and without $x commented out, and why:
>
> {
> my $x = "bar";
> sub foo {
> # $x # <- uncommenting this line changes the outcome
> return sub {$x};
> }
> }
> print foo()->();
>
That is confusing, but it is not because closures are confusing. It
is confusing because it is a BUG. In Perl 5, named subroutines are
not properly closed.
If the bug were fixed, the result would be 'bar' regardless of whether
or not $x was commented.
This would solve the problems with mod_perl also.
The right way to fix this is not to eliminate closures, or to require
declarations. The right way to fix this is to FIX THE BUG.
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