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polettix (7564)
Saturday July 05, 2008
10:12 AM
Variable holding a reference to itself
Today I did something that's totally insane:
$image = \$image unless ref $image;
The intent was normalising the input to a sub, which can be either the image or a reference to the image's data. My goal was to always have a reference.
After some debugging, it became clear that the "hold a reference to yourself" is plain wrong. I was relying on some obscure reasoning inside my brain, about the fact that taking that reference would magically "detach" the variable container from $image, just to take a reference to the container and put it into a new container in $image.
Luckily, sometimes Perl just refuses to DWIM, and with good reasons.
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Solutions (Score:1)
Obviously you want this:
However, that will make a copy of the value before taking a reference, eating up memory. What we would really like here is to attach the data to another container without copying it and then store a reference to that container in the current one. Well, with Data::Alias from the CPAN, we can:
Re: (Score:1)
$image_ref- because the sub was reasonably short and thus the name change was manageable. Thanks for the tip anyway!