You can get dynamic scoping in perl by prefixing things with `local`.

    $ENV{BLAH} = 'hi'; 
    $Some::Package::Var = 'there';

    {
      local $ENV{BLAH} = 'hello'; 
      local $Some::Package::Var = 'world';
      

      # this call will see 'hello' and 'world'
      some_method()
    }

    # this call will see 'hi' and 'there'
    some_method()

All the caveats with playing with globals above notwithstanding, it's more useful in practice as a way to get a 'slightly different copy of an object':

    my $a = { hello => 'world', other => 'stuff'};
    
    {
      delete local $a->{other};
      print "$a->{hello} $a->{other}\n";
    }
    
    print "$a->{hello} $a->{other}\n";

this gives

    world
    world stuff

Great way for setting up log contexts etc that automatically get removed after the scope exits...