#!/usr/bin/perl -w
use strict;

my $x = 1;
my $f = sub { $x };
{
    my $scope= tempSet( \$x, 2 );
    print $f->(), "\n"; # => 2
}
print $f->(), "\n"; # => 1

sub TempSet::DESTROY { shift(@_)->() }
sub tempSet {
    my( $sv, $new )= @_;
    my $prior= $$sv;
    my $restore= bless
        sub { $$sv= $prior },
        'TempSet';
    $$sv= $new;
    return $restore;
}