package SharedvariablesM;

use strict;
use warnings;

sub new {
    my $class = shift;

    my $self = {
      # we store here all shared variables, but this is done automatic
      store => {}
    };
    bless $self, $class;

    return $self;
}

sub value {
  my $self = shift;
  my $name = shift;
  # optional parameter for setting the $DEBUG to a new value
  # if this new-value is absent the we just return current value of $DEBUG
  my $newvalue = shift;

  # optional boilerplate to keep track who called us and from where:
  my $parent = (caller(1))[3]; if( ! defined($parent) ){ $parent = 'main' }
  my $whoami = ( caller(0) )[3].'()';

  my $itsnewname = ! exists $self->{'store'}->{$name};

  if( defined $newvalue ){
    if( $itsnewname ){
      warn "$whoami (via $parent) : creating new variable '$name'..."
    } else {
      warn "$whoami (via $parent) : modifying '$name' from ".$self->{'store'}->{$name}." to $newvalue";
    }
    $self->{'store'}->{$name} = $newvalue
  } elsif( $itsnewname ){
      die "$whoami (via $parent) : you are creating a new shared variable named '$name' without a value unless you have the variable name wrong!"
  }

  return $self->{'store'}->{$name}
}
# clone ourselves and return new object
sub clone {
  my $self = shift;
  my $aclone = SharedvariablesM->new();
  for my $name (keys %{$self->{'store'}}){
    $aclone->value($name, $self->value($name));
  }
  return $aclone
}

sub toString {
  my $self = shift;
  my $ret = __PACKAGE__." here is what I store:\n";
  for my $name (sort keys %{$self->{'store'}}){
    $ret .= $name . '=>' . $self->{'store'}->{$name} . "\n"
  }
  return $ret;
}
1;