package Base;

sub AUTOLOAD {
    (my $meth = our $AUTOLOAD) =~ s/([^:]+)$/$1/;

    if ( $meth =~ /^is_/ ) {
        return;
    }

    # ????
}

package Foo;

our @ISA = qw( Base );

sub is_foo { 1 }

package Bar;

our @ISA = qw( Base );

sub is_bar { 1 }

# And so forth