note
Xiong
<blockquote><i>I am trying to follow this as I use hashes all over the place. What exactly is a soft reference.</i></blockquote>
<p>[tangent], you'll get plenty of explanations of symbolic references. But even after you understand them well it may not be clear how <b>hashes</b> come into this, in almost the same breath.
</p>
<p>To recap, [moritz] [id://952448|offered hashes] as an alternative to hard references. There was some discussion of this and [JavaFan] [id://952626|noted] hashes can invite some of the same issues <c>strict 'refs'</c> is meant to avoid. You may not see the connection; it took me a moment to pick it up.
</p>
<p>Seen one way, <c>use strict;</c> is a typo-catcher. In the simple case:
</p>
<c>
our $x13 = 'foo';
print $x31;
</c>
<p>... may not work as you expect because you really meant to type <c>$x13</c> both times. But <c>use strict;</c> will complain that you did not declare <c>$x31</c> and so the typo is caught.
</p>
<p>If you attempt to take a hard reference and make a typo, you'll get an error, too. But if you take a <i>symbolic</i> reference and don't <c>use strict;</c> then you will not get early notice of your typo.
</p>
<p>Where hashes begin to resemble (in a certain mental state) symbolic references is when you start stuffing a lot of unrelated data into a hash with literal keys; and then later you want to take something out:
</p>
<c>
my %hash;
$hash{boy} = 'Arnold';
$hash{pension_balance} = 172.50;
$hash{filehandle} = $fh;
print $hash{pensionbalance};
</c>
<p>The typo will not be caught, with or without <c>use strict;</c> instead, perl will happily <b>autovivify</b> <c>$hash{pensionbalance}</c> for you and immediately print it... although it's <b>undefined</b>. This can be an annoying thing to track down.
</p>
<p>For more on this, see [id://953289], where I demonstrate exactly this kind of risky approach... and note that it's <i>almost as evil</i> as global variables. I would not even have mentioned it if the OP didn't seem solidly committed to globals in the first place. As questionable as it is, I still think it's better than <c>no strict 'refs';</c>
</p>
<div class="pmsig"><div class="pmsig-704000">
<i>I'm not the guy you kill, I'm the guy you buy.</i> —Michael Clayton
</div></div>
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