I've found that limiting the scope of my temporaries has reduced my debugging time. So when I need a "scratch variable" for a few steps, or need to set something dangerously global like $/ for a few steps, I pop open a block and do the work there.

Doing so makes it very clear to the reader that this variable doesn't need a long lifetime, and even ensures that the action won't collide with a larger-scoped variable. It's a slick trick, and works nicely.

I've also recently started using the idiom of a one-iteration foreach loop to "name" a value rather than setting up a temporary, like: 

for ($some->complicated(@value)->{$to_fetch}) {
  print; # print it
  print LOGFILE $_; # and to the logfile
  substr($_, 0, 1, ""); # remove its first character
}

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It's a nice idiom, and is also the explanation of why Larry intentially allows foreach to be spelled "f-o-r". And the "backwards foreach" makes it even easier: 
do_this($_), do_that($_, @moreargs) for $some{$complicated}{$value};

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-- Randal L. Schwartz, Perl hacker

In reply to On scoping temporaries or global settings by merlyn
in thread One-shot code critique by patgas

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