That is a great book. I read it several times, and foundation of the knowledge I have of references to this day is owed to that book.

Personally, unless absolutely necessary, I try to stay away from having to set attributes individually. I prefer to try to set these within larger public methods that set/reset the attribute then do something functional with it, like this:

sub write_graffiti {
    my $self = shift;
    my %params = @_;
 
    $self->{colour} = $params{colour} if defined $params{colour};

    # spray paint wall with the colour,
    # whether new or existing
}
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When I do need to expose a direct setter/getter for an individual attribute, I do both in one fell swoop, in a more generic sub:

sub colour {
    my $self = shift;
    my $colour = shift if @_;

    $self->{colour} = $colour if defined $colour;

    return $self->{colour};
}
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