Re^2: Modify the Object

[Your Mother]

Your amendment is fine but I prefer the idiom tobyink showed. It's terse and lends itself to simple flow validation–

# use Carp;
sub access_A {
    my $self = shift;
    $self->{A} = shift if @_;
    croak "Too many arguments to access_A" if @_;
    $self->{A};
}