# localize
local $a= 42;
# works like:
my $saved= $a;
$a= undef;
$a= 42;

# restore
# works like
$a= $saved;

##</code><code>##

local $x;
*x= \$y;  # point the scalar slot to alias $y
#...
# $x goes back to pointing to its own slot when restoring.