Altering the Return Value: Prewrappers

        $return = bless sub {$prereturn=1}, 'Hook::LexWrap::Cleanup';
        my $dummy = $wrapper{pre}->(@_, $return) if $wrapper{pre};

• But wait

• What about:

        In a pre-wrapper, $_[-1] is -- for obvious reasons -- undef. 

• Since $return is a blessed subroutine, why does the prewrapper see undef?

        package Hook::LexWrap::Cleanup;

        use overload 
                q{""}   => sub { undef },
                q{0+}   => sub { undef },
                q{bool} => sub { undef };

• The object is overloaded to look like undef even though it isn't

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Copyright © 2003 M. J. Dominus