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perlperl asked
Last Modified: 2010-03-05
in object oriented perl
what is is the difference between the foll two variables

sub new
  my $proto = shift;
  my $class = ref($proto) || $proto;

  my $this = {};

  bless($this, $class);

  my %hash = @_;

  $this->{NAME} = $hash{NAME} if( defined($hash{NAME}) );

  # set some internal defaults
  $this->{_NAME}    = DEFAULT_NAME;

  return $this;

also. what does the following does????
  my $proto = shift;
  my $class = ref($proto) || $proto;
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my $proto = shift;
shift will take the first value of the array off and returns it, shortening the array by 1 and moving everything down.  If no array is provided, will shift @_ within subroutines.  @_ contains the arguments passed to the subroutine.  When creating an object, the first argument to the new function is the class name.
For more:  http://perldoc.perl.org/functions/shift.html

my $class = ref($proto) || $proto;
The ref function will return the type of object, or empty string if no reference is given.  In the case of empty string, the "|| $proto" will return $proto.
For more: http://perldoc.perl.org/functions/ref.html
1) not much. Usually the _var form is used to denote itnernal variables which should not be used by people using your package.

2) new function is passed the class name as the first argument.
$proto = shift ;
#gets the class or the instance name name.
my $class = ref($proto) || $proto;
#makes it an instance object as well. So, qutoing fro perldoc perltoot, you can say
$me = Person->new() ;
$you = $me->new() ;

oops sorry, dodnt see that it had already been posted and accepted !!

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