This looks like OOP code:

package a;

sub new {
 my $class = shift;
 my $self = {};
 bless $self,$class;
 return $self;
}

my $obj = new a ();
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However, the last line there is generally considered poor style. Try:

my $obj = "a"->new();
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But these lines seem to bear no relation to OOP:

$obj ->{$self}{avalue}=10;
print $obj->{$self}{avalue};
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Try something like this:

{
  package a;
  sub new {
    my $class = shift;
    my $self = {};
    bless $self,$class;
    return $self;
  }
  sub avalue {
    my $self = shift;
    $self->{avalue} = shift if @_;
    return $self->{avalue};
  }
}

my $obj = "a"->new();
$obj->avalue(10);           # set
print $obj->avalue, "\n";   # get
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That should give you an idea how OOP works. That said, I'd recommend using Moose or Moo as a way of reducing repetitive OOP code...

{
  package a;
  use Moo;
  has avalue => (is => 'rw');
}

my $obj = "a"->new();
$obj->avalue(10);           # set
print $obj->avalue, "\n";   # get
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