$ perl -E '
    my $x = { a => 1, b => 2 };
    say "@$x{qw{a b}}";
    {
        local @$x{qw{a b}} = (3,4);
        say "@$x{qw{a b}}";
    }
    say "@$x{qw{a b}}";
'
1 2
3 4
1 2