http://www.perlmonks.org?node_id=564539


in reply to local() for scalar file slurping

How did I never read anything about the usefulness of local() for such purposes before this? Am I living under a rock?

Indeed, I was blind to local for much of my early Perl years (yes, I literally mean years) also. I read the warnings to never use it, and I took them dead seriously. Once I started toying more, though, I found that there are indeed some good uses of local. I consider what you've shown one of them.

Another one is that you can localize a particular element in an array or a hash. Much as with local in general, this has many bad uses and a few good ones, but it's still a neat trick. Example:

    my %hash = qw(one 1 two 2);
    {
        local $hash{one} = $hash{one};
        $_++ for values %hash;
        print "$hash{one} $hash{two}\n"; # prints "2 3"
    }
    print "$hash{one} $hash{two}\n"; # prints "1 3"

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Notice the change to $hash{two} is permanent, but the change to $hash{one} is localized. Pretty cool, eh?

In Section Meditations