Oh wise monks,

So, I've inherited some code, and I've been assigned the task of enhancing it in various ways, but I am constrained along various dimensions. In particular, I cannot change the class/package structure, nor how packages and objects are related to one another. And I'm stuck trying to understand what's happening here...

The code here is a minimal example of what I have. The method I'm trying to understand is Q::bar. 


package P;

sub new {
    my ($proto) = @_;
    my $self = {};
    bless $self => $proto;
}

sub foo {
    print "P: foo\n";
}

sub bar {
    print "P: bar\n";
}

package Pprime;

@Pprime::ISA = qw(P);

sub new {
    my ($proto) = @_;
    my $self = {};
    bless $self => ref($proto) || $proto;
}

package Q;

sub new {
    my ($proto) = @_;
    my $self = {};
    bless $self => $proto;
}

sub bar {
    my $self = shift;
    print "Q: bar\n";
    $self->SUPER::bar();
}

sub test {
    my $self = shift;
    $self->foo();
    $self->bar();
}

package Qprime;

@Qprime::ISA = qw(Q Pprime);

sub new {
    my ($proto) = @_;
    my $self = {};
    bless $self => ref($proto) || $proto;
}

package main;

my $obj = Qprime->new();
$obj->test();

[download]

Running this script yields the following output: 

P: foo
Q: bar
Can't locate object method "bar" via package "Q" (perhaps you forgot t
+o load "Q"?) at ./demo.pl line 40.

[download]

Now as it turns out, I can get around the problem because I'm able to rename Q::bar, at which point the calls to P::foo and P::bar act the same. But I just don't understand why the SUPER doesn't work.

I appreciate any wisdom you can shed on the issue.
--roundboy

In reply to Weird inheritance and SUPER by roundboy

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