hperange:

I generally avoid that practice, as it's easy to get confused. Sometimes I want a shorthand variable for a member, like color, but also want to use the hashref, too. In that case, I normally have two variables $rColor and $color, where $rColor is the reference. This keeps them visually distinct, but related (to me, anyway). If I wasn't using the reference, I'd avoid the issue altogether by making a subroutine that simply returned the color:

$class = '...';
$color = color_of($class);

sub color_of {
    $class = shift;
    my $t = first { $class =~ /$_->{'re'}/ } @rules;
    return $color->{'color'};
}

[download]

Having said all that, it really depends on usage. I occasionally find it more convenient to reuse the variable. In limited scope, it can often be clear and obvious enough to not warrant the extra effort:

for my $foo (...) {
    my $color = first { $class =~ /$_->{'re'}/ } @rules;
    $color = $color->{'color'};

    ...
}

[download]

With this bit, I'm setting up the variable at the top of the loop, so it's clear (to me) that the first line is simply an interim step. If the for body were longer, and I switched between the hash version and scalar version, it would be confusing. In this case, it would be nice if there were a simple way to do it in one go, like:

my $color = ${first { $class =~ /$_->{'re'}/ } @rules}->{'color'};

[download]

But if it exists, then I haven't found it.

...roboticus

When your only tool is a hammer, all problems look like your thumb.

In reply to Re: Data structure / hash reference question by roboticus
in thread Data structure / hash reference question by hperange

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