Perl leaves to the programmer the task of allocating the object storage, setting the dispatch table and initializing the object for greater flexibility.
In theory.

In practice, the overwhelming majority of the programmers screws this up, each and every time they create a class. I bet there are seasoned Perl programmers who haven't managed not not screw up.

Consider: 

package Colour;
sub new {bless {colour => $_[1]}, $_[0]}
sub colour {$_[0]{colour}}

package Age;
sub new {bless {age => $_[1]}, $_[0]}}
sub age {$_[0]{age}}

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Whee. Now I can make colour objects, and age objects: 
use Colour;
use Age;
my $c_obj = Colour::->new("orange");
my $a_obj = Age::->new(42);
print "I have an object with colour ", $c_obj->colour;
print "And another object aged ", $a_obj->age;

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Goodie. Now, if there was any flexibility, I'd be able to create a class that's both, using multiple inheritance, and without breaking encapsulation (that is, peeking and making use of the implementation of a parent class): 
package Age_and_Colour;
use Age;
use Colour;
our @ISA = qw[Age Colour];
sub new {
    my ($class, $age, $colour) = @_:
    ... Now what? ...
}

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If I call Age::->new, I get back an object initialized with an age, but no colour; but if I call Colour::->new, I get one with a colour, but no age.

Greater flexibility is fine, but if this requires a lot more effort from the programmer, it's pointless. That's like saying C has greater flexibility when it comes to regular expressions: it gives you a minimal string implementation, and leaves everything else to the programmer. Sure, you *can* make more fantastic regular expressions in C than in Perl, but I don't see many people actually doing that.

(cue the Pavlov reactions: "but you shouldn't use MI anyway")

In reply to Re^6: Perl "new" command by JavaFan
in thread Perl "new" command by akagrawal3

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