I do use unless occasionally, but only when it reads much more naturally than any alternative, and when the conditional expression is trivial. So in this case I certainly broke the second part of my own guidelines, and I probably broke the first as well.

When I’m trying to avoid an ‘unless’ I find myself using ‘not’ more than ‘!’ these days. So I’d probably write the expression as

next if not $x or $x->{as_of_rev} …

Perl Best Practices, page 96 & 97. Don’t use postfix-style modifiers other than if, and never use unless.

I point that out only because you recommended that I read the book just 3 weeks ago (I did, and this is exactly what it said could happen). I do think the next belongs on the left though.

Cheers
adam

# at this point $current_revision is > $x, save the first one.

then stick the ‘next’ above the comment. That gives me a reference for
the if/or/unless/and logic — and makes it easier for whomever follows
me to see if I did it right!

I opted not to factor out the “->{ $args{cid} }” because it didn’t seem worth digging deeper into the data structure for the very small gain (relative to avoiding calls to get_data). If I need to revisit the code again for performance reasons I’d change it.

My mistake? The “> $current_revision” should have been “<= $current_revision”. I think the combined effect of changing from an ‘if’ to a ‘next’ with an ‘unless’ threw me off. Like a double negative.

Second, I think it’d make more sense to extract out the “->{ $args{cid} }” part too. Any reason you didn’t?

I’m afraid I can’t spot the error though. Looking at the original code is making my brane hurt so I’m giving up now ;)