In the second code sample below, package LM has a subroutine mylol. In this subroutine, the object slot data is manually changed from it's initialized value and then set back to the original value before the subroutine exits.

I was hoping to use lexical scope or something to avoid manually setting the value back to its original value: 

sub mylol {
  my $self=shift;
  {
    local $self; $self->{data} = {newdata => 1};
    $lol = super();
  }
}

[download]
but I didnt like the idea of using package variables to achieve it. Is there some way to create a scope and change an object and then have it pop back to the initial settings? 
package L;

use Moose;

has 'data' => (
    is      => 'rw',
    trigger => \&maybe_morph
);

sub maybe_morph {
    my ($self) = @_;
    if ( $self->can('morph') ) {
        $self->morph;
    }
}

sub lol {
  my $self=shift;

  [ lol => 'haha' ];
}

sub tree {
    warn 'tree';
    $_[0];
}

sub prune {
    warn 'prune';
}

after 'tree' => sub { warn 'aftertree'; };

1;

package LM;
use Moose;

extends qw(L);

override 'lol' => \&mylol;

sub mylol {
    my ($self) = @_;

    # get data from object
    my $original_data = $self->data;
    my $lol;

    # set data to something superclass can use, 
    # avoid $self->data($val) because that will 
    # cause the trigger to fire
    $self->{data} = { newdataset => 1 };
    $lol = super();


    # now that superclass has been called
    # set $self->{data}
    $self->{data} = $original_data;

    use Data::Dumper;
    warn Dumper( $self->{data} );
    $lol;
}

package main;

my $b = LM->new( data => { m => 'em' } );
$b->mylol;

1;

[download]




The mantra of every experienced web application developer is the same: thou shalt separate business logic from display. Ironically, almost all template engines allow violation of this separation principle, which is the very impetus for HTML template engine development.

-- Terence Parr, "Enforcing Strict Model View Separation in Template Engines"

In reply to creating an altered clone of a Moose object for a limited scope by metaperl

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