http://qs321.pair.com?node_id=1221412


in reply to Re^3: OO systems and Perl 5 (Was: Recap: Future of Perl 5)
in thread OO systems and Perl 5 (Was: Recap: Future of Perl 5)

Semantically, you are right.

But, that is not the issue Ovid raised in Recap: The Future of Perl 5.

In his proposal, Ovid seeks to reduce the number of required steps and simplify the syntax in Perl 5's OO system.

As to why I said Python's OO system seems to have changed since Larry stole from it, see the Python 3 example:

class Dog: # Class Attribute species = 'mammal' # Initializer / Instance Attributes def __init__(self, name, age): self.name = name self.age = age # Instantiate the Dog object philo = Dog("Philo", 5)

__init__ is called with an already "blessed" ref to an already allocated container. __init__ only sets values to the objects's fields.

The 1-to-1 translation to Perl would be (using signatures to reduce "noise"):

package Dog; our $species = 'mammal'; sub __init__ ($class, $name, $age) { my $self = {}; $self->{name} = $name; $self->{age} = $age; bless $self, $class; } package main; my $philo = Dog->__init__('Philo', 5);

Even if we make __init__ more Perl-ish (still using signatures):

sub __init__ ($class, $name, $age) { my $self = bless {name => $name, age => $age}, $class; }

Ovid would still point out that Perl is requiring the programmer to perform 2 extra steps: Allocate the container and create a blessed reference to the container.

I don't know which version of Python Larry stole the OO system from, so I don't know what Larry changed. But, at least to me, Perl 5's classes look more like Smalltalk classes than Python 3 classes.