> Objects in Perl are implemented as a reference to an
> anonymous hash.
> The keys to the hash are the names of the members, and the
> values of
> the hash may be any scalar. This includes normal scalar
> values and
> references. Thus, a member of your object may be a
> reference to an
> array or a hash or it may be another object (reference to
> a hash) or a
> method (reference to subroutine). So you can have any
> level of nesting
> of objects-within-objects and arrays or hashes of other
> objects. You
> enumerate over array and hash members as you would
> enumerate over any
> array or hash given a reference to one of these.

> See the following documentation built into your
> installation of perl:

> 'perldoc perlreftut'    Perl references tutorial
> 'perldoc perldsc'       Perl data structures cookbook
> 'perldoc perllol'       Manipulating arrays of arrays in
> Perl
> 'perldoc perlboot'      Beginner's object-oriented
> tutorial

>> Objects in Perl are implemented as a reference to an anonymous hash.
>> The keys to the hash are the names of the members, and the values of
>> the hash may be any scalar. This includes normal scalar values and
>> references. Thus, a member of your object may be a reference to an
>> array or a hash or it may be another object (reference to a hash) or a
>> method (reference to subroutine). So you can have any level of nesting
>> of objects-within-objects and arrays or hashes of other objects. You
>> enumerate over array and hash members as you would enumerate over any
>> array or hash given a reference to one of these.

>> See the following documentation built into your installation of perl:

>> 'perldoc perlreftut'    Perl references tutorial
>> 'perldoc perldsc'       Perl data structures cookbook
>> 'perldoc perllol'       Manipulating arrays of arrays in Perl
>> 'perldoc perlboot'      Beginner's object-oriented tutorial

> Thanks for the info.  I have been using perl on and off but never tried
> its OO feature.
> I followed the example in perlcod perlboot but got an error.

> Here is my code
> --------------------

>    Cow->speak;

> { package Animal;
>  sub speak {
>    my $class = shift;
>    print "a $class goes ",$class->sound,"!\n";
>  }
> }

> { package Cow;
>  use vars qw(@ISA);
>  @ISA = qw(Animal);
>  print "Hi >$ISA[0]>\n";
>  sub sound {"Mooo"}
> }
> ---------------------
> After execution, I got

> C:\Perl\MDGS>
> C:\Perl\MDGS>
> C:\Perl\MDGS>Sample.pl
> Can't locate object method "speak" via package "Cow" at
> C:\Perl\MDGS\Sample.pl line 2.

> --------------------

> Does this mean perl can't recgnize @ISA?

> Thanks,
> pac

>>    Cow->speak;

> Which Cow, which speak?

>> { package Animal;
>>  sub speak {
>>    my $class = shift;
>>    print "a $class goes ",$class->sound,"!\n";
>>  }
>> }

>> { package Cow;
>>  use vars qw(@ISA);
>>  @ISA = qw(Animal);
>>  print "Hi >$ISA[0]>\n";
>>  sub sound {"Mooo"}
>> }
>> ---------------------
>> After execution, I got

>> C:\Perl\MDGS>
>> C:\Perl\MDGS>
>> C:\Perl\MDGS>Sample.pl
>> Can't locate object method "speak" via package "Cow" at
>> C:\Perl\MDGS\Sample.pl line 2.

>> --------------------

>> Does this mean perl can't recgnize @ISA?

>> Thanks,
>> pac

> Move your speaking cow to the point beyond the package
> declarations
> and she will no longer be silent.