# override the default accessor method for 'count'
    sub count {
        my $self = shift;
        if ( @_ ) {
            die 'count must be nonnegative' if $_[0] < 0;
            $self->{'MyObj::count'} = shift;
            warn "Too many args to count" if @_;
        }
        return $self->{'MyObj::count'};
    }

    package main;
    $x = new MyObj;
    print "\$x->count(5) = ", $x->count(5), "\n";
                            # prints '$x->count(5) = 5'

    print "\$x->count = ", $x->count, "\n";
                            # prints '$x->count = 5'

    print "\$x->count(-5) = ", $x->count(-5), "\n";
                            # dies due to negative argument!

=item Example 3

The constructor of a generated class can be passed a list
of I<element>=>I<value> pairs, with which to initialize the struct.
If no initializer is specified for a particular element, its default
initialization is performed instead. Initializers for non-existent
elements are silently ignored.

Note that the initializer for a nested class may be specified as
an object of that class, or as a reference to a hash of initializers
that are passed on to the nested struct's constructor.

    use Class::Struct;

    struct Breed =>
    {
        name  => '$',
        cross => '$',
    };

    struct Cat =>
    [
        name     => '$',
        kittens  => '@',
        markings => '%',
        breed    => 'Breed',
    ];


    my $cat = Cat->new( name     => 'Socks',
                        kittens  => ['Monica', 'Kenneth'],
                        markings => { socks=>1, blaze=>"white" },
                        breed    => Breed->new(name=>'short-hair', cross=>1),
                   or:  breed    => {name=>'short-hair', cross=>1},
                      );

    print "Once a cat called ", $cat->name, "\n";
    print "(which was a ", $cat->breed->name, ")\n";
    print "had two kittens: ", join(' and ', @{$cat->kittens}), "\n";

=back

=head1 Author and Modification History

Modified by Damian Conway, 2001-09-10, v0.62.

   Modified implicit construction of nested objects.
   Now will also take an object ref instead of requiring a hash ref.
   Also default initializes nested object attributes to undef, rather
   than calling object constructor without args
   Original over-helpfulness was fraught with problems:
       * the class's constructor might not be called 'new'
       * the class might not have a hash-like-arguments constructor
       * the class might not have a no-argument constructor
       * "recursive" data structures didn't work well:
                 package Person;
                 struct { mother => 'Person', father => 'Person'};


Modified by Casey West, 2000-11-08, v0.59.

    Added the ability for compile time class creation.

Modified by Damian Conway, 1999-03-05, v0.58.

    Added handling of hash-like arg list to class ctor.

    Changed to two-argument blessing in ctor to support
    derivation from created classes.

    Added classname prefixes to keys in hash-based classes
    (refer to "Perl Cookbook", Recipe 13.12 for rationale).

    Corrected behaviour of accessors for '*@' and '*%' struct
    elements.  Package now implements documented behaviour when
    returning a reference to an entire hash or array element.
    Previously these were returned as a reference to a reference