... or doing some weird and nasty local/typeglob hackery.

Keep in mind that talking about Perl5, the specification is the implementation. So that "weird and nasty hackery" is, by flipping the enlightenment bit, Higher Order Perl... ;)

I'd say - dealing with Perl5, expect dragons. But they are teaching dragons. We even do have one here...

update:

Of course, this too is solveable, Ovid had a hack where he assigned a name to the __ANON__ typeglob slot using local I don't recall the details, and there is also Sub::Name on the CPAN. But either way your now depending on an XS module (Sub::Name) or doing some weird and nasty local/typeglob hackery.

Nah... look, ma, no XS, no __ANON__:

sub AUTOLOAD {
    my $self = shift;
    my $type = ref($self)
        or croak "$self is not an object";

    my $name = $AUTOLOAD;
    $name =~ s/.*://;   # strip fully-qualified portion

    unless (exists $self->{_permitted}->{$name} ) {
        croak "Can't access `$name' field in class $type";
    }
    eval ("sub $AUTOLOAD {
        my (\$self,\$value) = \@_;
        \$self->{$name} = \$value if defined \$value;
        \$self->{$name};
    }");
    die $@ if $@;
    goto &$AUTOLOAD;
}
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