For me 
unless ($expression){
  # do something
}

[download]
is never elegant. I'll always plump for 
if (not $expression){
 # do something
}

[download]
especially if, as in this case $expression includes some boolean arithmetic. I do use it for early exits from loops though. I can read 
while (<$fh>){
 next unless /\S/;
 #
}

[download]
without too much trouble (as long as it's simple).

As soon as an expression has a not an and and an or in it I'm almost sure to get it wrong and it often points to a poor algorithm which some refactoring can fix. Either that or put it into sub so I can say 

if (work_to_do($args)){
 # do some work
}

[download]
and test the living daylights out of it.

Did I mention I've had awful trouble with boolean arithmetic? :-)

In reply to Re^2: This is why Perl is so frustrating by wfsp
in thread This is why Perl is so frustrating by eggmatters

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