How can I redefine Perl class methods?

Question

The question \"How can I monkey-patch an instance method in Perl?\" got me thinking. Can I dynamically redefine Perl methods? Say I have a class like this one:

Answer 1

Not useful in your case but had your class been written in Moose then you can dynamically override methods using its Class::MOP underpinnings....

{
    package MyClass;
    use Moose;

    has 'val' => ( is => 'rw' );

    sub get_val {
        my $self = shift;
        return $self->val + 10;
    }

}

my $A = MyClass->new( val => 100 );
say 'A: before: ', $A->get_val;

$A->meta->remove_method( 'get_val' );
$A->meta->add_method( 'get_val', sub { $_[0]->val } );

say 'A: after: ', $A->get_val;

my $B = MyClass->new( val => 100 );
say 'B: after: ', $B->get_val;

# gives u...
# => A: before: 110
# => A: after: 100
# => B: after: 100