With Guard, you get to set up a call back when the scope is left to clean up whatever.

Ah - sorry - I meant that the localizing code returns such a guard object, so that the caller can then decide whether to clean up at exit or to pass that guard on upwards again.

I'm still unaware of where that implicit localization-at-a-distance would be good design. The following code seems to me to solve the problem in a pure-perl fashion, and keeps the localization somewhat explicit, instead of prodding through the enclosing pads by name:

#!perl -w
use strict;
use Guard;

sub alias {\@_};
sub localize {
    my @values = @{ +pop }; # or any other convenient method
    my $aliases=alias(@_);
    my @saved= @_;

    #warn Dumper \@saved;
    $_[$_] = $values[$_] for 0..$#values;
    guard {
        $aliases->[$_]=$saved[$_] for 0..$#saved;
    };
};

my ($a,$b)=('a','b');

print "Start\n";
print qq($a $b),"\n";

my $restore=localize($a,$b,['foo','bar']);

print "Localized\n";
print qq($a $b),"\n";
undef $restore;
print "Restored\n";
print qq($a $b), "\n";
__END__
Start
a b
Localized
foo bar
Restored
a b

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In reply to Re^5: Scope::Upper localize? by Corion
in thread Scope::Upper localize? by Anonymous Monk

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