Re: Modify the Object

Can some one tell how to change the values of object?

The usual way is to provide an accessor method in the First package:

sub access_A
{
    my ($self, $new_a) = @_;
    $self->{A} = $new_a if defined $new_a;
    return $self->{A};
}
[download]

Then you can call this method in the main program as follows:

my $obj = new First('A' => 'red',
                    'B' => 'green');
print "Here, A's colour is ", $obj->access_A(), "\n";
$obj->access_A('yellow');
$obj->teller();
[download]

which will output:

Here, A's colour is red
$VAR1 = bless( {
                 'A' => 'yellow',
                 'B' => 'green'
               }, 'First' );
[download]

By the way, in the definition of sub teller there should not be any parentheses after the method name. The parentheses create a prototype, saying that the sub takes no arguments — which is unnecessary, and, in this case, incorrect.

Hope that helps,

Update: Added defined to the test in sub access_A, to solve the problem identified by tobyink, below.

Athanasius <°(((>< contra mundum

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Re^2: Modify the Object by tobyink (Canon) on Oct 02, 2012 at 16:02 UTC
Your example accessor has a problem: `package Local::Class; sub new { my $class = shift; bless +{ A=>'default' }; } sub access_A { my ($self, $new_a) = @_; $self->{A} = $new_a if $new_a; return $self->{A}; } package main; use 5.010; my $obj = Local::Class->new; $obj->access_A(1); say $obj->access_A; # says 1 $obj->access_A(2); say $obj->access_A; # says 2 $obj->access_A(0); say $obj->access_A; # says 2 !!!` [download] A better way of writing that accessor would have been: `sub access_A { my $self = shift; $self->{A} = shift if @_; return $self->{A}; }` [download] (Or even better, use Moose so that you don't need to worry about writing accessors.) `perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'`	[reply] [d/l] [select]
Re^2: Modify the Object by Your Mother (Archbishop) on Oct 02, 2012 at 17:06 UTC
Your amendment is fine but I prefer the idiom tobyink showed. It's terse and lends itself to simple flow validation– `# use Carp; sub access_A { my $self = shift; $self->{A} = shift if @_; croak "Too many arguments to access_A" if @_; $self->{A}; }` [download]	[reply] [d/l]