另一个简单的Perl问题……（散列到对象数组）

Question

I'm working on creating a Graph class in Perl and I'm hoping to have each Graph contain Nodes. Each Node has some properties and also (for now) an array which contains references to each other node it is connected to. So far I have this definition of a node:

use strict; package Node;

sub new{
my $class = shift;
my @array = ();
my $array_r = \@array;
my $self = {
    code => undef,
name => undef,
country => undef,
continent => undef,
timezone => undef,
coordinates => undef
population => undef,
region => undef,
arrayRef => $array_r,
@_,

}; bless $self, $class; return $self; } Yet upon calling the following function from my main script:

sub getSetArray{
    my $self = shift;
my $param = shift;
my $temp = $self->{arrayRef};
push(@{$temp}, $param) if defined $param;
return $self->{arrayRef};
} 

and trying to iterate over a Node's array(which will contain more Nodes that it is connected to):

my $firstnode = Node->new();  # Node constructor should have @array of
my $secondnode = Node->new();

$firstnode->getSetCode("test"); 
print "The current code is ", $firstnode->getSetCode(), "\n";

my $array_r = $firstnode->getSetArray($secondnode);

$array_r = $firstnode->getSetArray($firstnode);

foreach my $obj (@{$array_r}){
    print $obj;
}

This prints out Node=HASH(0x10092bb00)Node=HASH(0x100907bd8). Which leads me to believe that I am dealing with an array containing 2 nodes (this is what I want). But upon attempting to call any methods of this $obj's I am told that I

Can't call method "getSetNode" without a package or object reference.

I had already previously blessed these two objects when calling new on these nodes. So I'm not sure why they aren't recognized as Nodes and I can't call their methods....

EDIT -

foreach my $obj (@{$array_r}){  
    print $obj->getSetCode();
}

where getSetCode() is

sub getSetCode{
    my $self = shift;
    my $param = shift;
    $self->{code} = $param if defined $param;
    return $self->{code};
}

Answer 1

Show how you are trying to call getSetNode on $obj, and the code of getSetNode?

By the way, $temp isn't needed; you can directly do:

push @{ $self->{arrayRef} }, $param if defined $param;

Maybe helpful to you: http://perlmonks.org/?node=References+quick+reference

Also note that you are setting up a cyclical data structure ($firstnode indirectly referencing itself) that perl won't garbage collect automatically, even when all external references go away; you can fix this (if this is even a concern) with:

if (defined $param) {
    push @{ $self->{arrayRef} }, $param;
    Scalar::Util::weaken( $self->{arrayRef}[-1] ) if $param == $self;
}

As far as your problem goes, putting all your code together (and adding a missing , on the coordinates line) into this:

use warnings;
use strict;
package Node;

sub new {
    my $class = shift;
    my @array = ();
    my $array_r = \@array;
    my $self = {
        code => undef,
        name => undef,
        country => undef,
        continent => undef,
        timezone => undef,
        coordinates => undef,
        population => undef,
        region => undef,
        arrayRef => $array_r,
        @_,
    };
    bless $self, $class;
    return $self;
}

sub getSetArray{
    my $self = shift;
    my $param = shift;
    my $temp = $self->{arrayRef};
    push(@{$temp}, $param) if defined $param;
    return $self->{arrayRef};
} 

sub getSetCode{
    my $self = shift;
    my $param = shift;
    $self->{code} = $param if defined $param;
    return $self->{code};
}


my $firstnode = Node->new();  # Node constructor should have @array of
my $secondnode = Node->new();
$secondnode->getSetCode("test2");

$firstnode->getSetCode("test"); 
print "The current code is ", $firstnode->getSetCode(), "\n";

my $array_r = $firstnode->getSetArray($secondnode);

$array_r = $firstnode->getSetArray($firstnode);

foreach my $obj (@{$array_r}){  
    print $obj->getSetCode(), "\n";
}

gives this output for me:

The current code is test
test2
test