Embedded Class::Struct Misbehaviour

shemp has asked for the wisdom of the Perl Monks concerning the following question:

Ive been having trouble embedding Class::Struct as the type of an element of another Class::Struct Following the example in The Perl Cookbook section 13.5 "Using Classes as Structs", i've created the following code:

#!/usr/bin/perl -w

use Class::Struct;


struct Person   =>  {
    name    =>  '$',
    age     =>  '$',
};

struct Family   =>  {
    head        =>  'Person',
    address     =>  '$',
    members     =>  '@',
};

{
    my $folks = Family->new();
    my $dad = $folks->head();

    print "dad = $dad , its a " . ref($dad) . "\n";

    $dad->name("John");
    $dad->age(34);
}
[download]

Now, the output from this program is:
Use of uninitialized value in concatenation (.) or string at cook_test.pl line 21.
dad = , its a
Can't call method "name" on an undefined value at cook_test.pl line 23.

shouldn't ref($dad) say "Person" ?
it appears that $folks->head() is returning an unitialized scalar.
BTW i'm running Perl 5.8.0 for sun4-solaris
any insight into what im missing would be great.
related: anybody know if Class:StructTemplate has evolved at all. the CPAN documentation is from 12-26-2000, and i do want to serialize structs into MySQL
thanks much

Comment on Embedded Class::Struct Misbehaviour Download Code

Replies are listed 'Best First'.
Re: Embedded Class::Struct Misbehaviour by shemp (Deacon) on Nov 06, 2002 at 18:30 UTC
Alright, i figured out the problem. The Perl 5.8.0 distro includes Struct.pm v0.61 which doesnt work right. I copied v0.59 from another box i had and it worked.	[reply]
Re: Embedded Class::Struct Misbehaviour by jdporter (Paladin) on Nov 06, 2002 at 18:34 UTC
shouldn't ref($dad) say "Person" ? Not automatically. As the example in the Class::Struct doc shows, you need to initialize the field. Class::Struct enforces that it's the right type, but doesn't create the variable for you. You can do this: `$folks->head( new Person .... );` [download] to initialize the field.	[reply] [d/l]
Re: Re: Embedded Class::Struct Misbehaviour by shemp (Deacon) on Nov 06, 2002 at 20:23 UTC
Actually, with the code from the original post, with Class::Struct 0.59, the print statement does report that $dad is a 'Person'. I'm new to Class::Struct, (should've started using it years ago), and don't exactly know what the proper behaviour is supposed to be, just writing little test progs to figure it out. I love it though. thanks	[reply]