package NeedsAName;

sub TIEHASH {
    my ($class, $ref) = @_;
    return bless \$ref, $class;
}

sub FETCH {
    my ($self, $key) = @_;
    return substr $$$self, $key, 1;
}

sub STORE {
    my ($self, $key, $data) = @_;
    return substr($$$self, $key, 1) = $data;
}

sub CLEAR {
    my ($self) = @_;
    $$$self = '';
}

sub DELETE {
    my ($self, $key) = @_:
    $self->STORE($key, '');
}

sub EXISTS {
    my ($self, $key) = @_;
    return $key <= length $$$self; 
}

sub FIRSTKEY {
    my ($self) = @_;
    return length $$$self ? 0 : undef;
}

sub NEXTKEY {
    my ($self, $lastkey) = @_
    return length $$$self > $lastkey ? $lastkey + 1 : undef;
}

# tie %foo, 'NeedsAName', \$string;