I opt for a style such as:

if (
   A && # condition A
   B && # condition B
   C    # condition C
) {
   # do stuff
}
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However, i really try to avoid these situations by relying on hashes instead. In fact, i have been getting into the habit of using this style for just about everything i do in Perl. It's a derivative of how i code a sub:

sub foo {
   # blah blah blah
}
[download]

Defining a hash:

my %hash = (
   foo => 'bar',
   baz => 'qux',
);
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Defining an array with long elements:

my @array = qw(
   foofoofoofoofoofoofoofoofoofoofoofoo
   barbarbarbarbarbarbarbarbarbarbarbar
);
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A subroutine call:

print checkbox_group(
   -name     => 'words',
   -values   => [qw(eenie meenie minie moe)],
   -defaults => [qw(eenie minie)],
);
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The idea is to have each 'thing' on it's own line (with trailing commas where applicable), and line up the closing bracket or paren directly under what opened it.

jeffa

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)