How to get reference to parent class subroutine perl - perl

Question

I have a situation where in child class, I need a reference of subroutines defined in parent class which I need to pass to some other class which would execute them.
So I was wrote following sample modules for testing the same.
Parent1.pm
package Parent1;
sub new {
my ($class, $arg_hash) = #_;
my $self = bless $arg_hash, $class;
return $self;
}
sub printHello{
print "Hello\n";
}
sub printNasty{
print "Nasty\n";
}
1;
Child1.pm
package Child1;
use base Parent1;
sub new {
my ($class, $arg_hash) = #_;
my $self = bless $arg_hash, $class;
return $self;
}
sub testFunctionReferences{
my ($self) = #_;
# Case 1: Below 2 lines of code doesn't work and produces error message "Not a CODE reference at Child1.pm line 18."
#my $parent_hello_reference = \&$self->SUPER::printHello;
#&$parent_hello_reference();
# Case 2: Out of below 2 lines of code, 1st line executes the function and produces output of "Hello\n" but 2nd line doesn't work and produces error message "Not a CODE reference at Child1.pm line 23."
#my $parent_hello_reference2 = \$self->SUPER::printHello;
#&$parent_hello_reference2();
# Case 3: does not work either. Says "Undefined subroutine &Child1::printNasty called at Child1.pm line 27"
#my $parent_nasty_reference = \&printNasty;
#&$parent_nasty_reference();
# Case 4: works. prints "World\n" as expected
#my $my_own_function_reference = \&printWorld;
#&$my_own_function_reference();
# Case 5: works. prints "Hello\n" and "Nasty\n" as expected
#$self->printHello();
#$self->SUPER::printNasty();
# Case 6: does not work produces error "Undefined subroutine &Child1::printHello called at Child1.pm line 38"
#printHello();
return;
}
sub printWorld{
print "World\n";
}
test.pl
#!/usr/bin/perl
use Child1;
my $child = Child1->new({});
$child->testFunctionReferences();
So my questions are:
As in case 1, what is the correct syntax to get a reference to parent subroutine?
When I use inheritance, how can I call the parent function directly as in case 6? Is it even possible in perl?
When case 5 works then why not case 6?
Any insights are appreciated. Thanks

Answer 1

If printHello is a subroutine, use
my $sub = \&Parent::printHello;
If printHello is a method, use
# This line must appear inside of the Child package.
my $sub = sub { $self->SUPER::method(#_) };
If you want a code reference, you need a subroutine to reference, and this creates one.
In both cases, you can call the sub using
&$sub();
or
$sub->();
(I find the latter cleaner, but they are otherwise equivalent.)

Answer 2

I figured out another method to get a reference to a parent class subroutine using 'UNIVERSAL' module 'can' method.
#Parent.pm
package Parent;
sub new {
my ($class, $arg_hash) = #_;
my $self = bless $arg_hash, $class;
return $self;
}
sub printHello{
print "Parent Hello Called\n";
}
1;
#Child.pm
package Child;
use base Parent;
sub new {
my ($class, $arg_hash) = #_;
my $self = bless $arg_hash, $class;
return $self;
}
sub getParentSubReference{
my ($self) = #_;
return $self->can('printHello');
}
1;
#test.pl
#!/usr/bin/perl
use Child;
my $obj = Child->new({});
my $ref = $obj->getParentSubReference();
&$ref();
#Output
Parent Hello Called