Question

I started learning how to make a module in perl with perltoot:

 package Person;
 use strict;

 my($NAME, $AGE, $PEERS) = ( 0 .. 2 );

 sub new {
    my $self = [];
    $self->[$NAME] = undef;
    $self->[$AGE] = undef;
    $self->[$PEERS] = [];
    bless($self);
    return $self;
 }

 sub name {
    my $self = shift;
    if (@_) { $self->[$NAME] = shift }
    return $self->[$NAME];
 }

 sub age {
    my $self = shift;
    if (@_) { $self->[$AGE] = shift }
    return $self->[$AGE];
 }

 sub peers {
    my $self = shift;
    if (@_) { @{ $self->[$PEERS] } = @_ }
    return @{ $self->[$PEERS] };
 }

 1;

• I would like to know how, if possible
  with sample code should I threat any
  errors within the module and outside
  it ?

For example:

 use Person;
 $test= Person->new() or die Person->Error;

or

sub new {
   my $self = [];
   $self->[$NAME] = undef;
   $self->[$AGE] = undef;
   $self->[$PEERS] = [];
   bless($self);
   #########
   # some error happened here and I need to say something
   #########
   return $self;
}

• If I call anything else within the
  module that had a error, problem,
  missing argument how is the correct
  way to tell there was an error ?

PS: Hope my question is not too off and hi everyone 🙂

Answer 1

Carp routines can be used to report errors.

use Carp qw{ croak };

sub new {
    my $self        = {};
    $self->{$NAME } = undef;
    $self->{$AGE  } = undef;
    $self->{$PEERS} = [];

    # replace the following with something appropriate
    if ($error_occurred) {
        croak 'Something did not work right';
    }

    return bless, $self;
}