++ for letting us know the resolution.

On the comma thing. I have a habit of starting out with a lines like

$i++ if $some_condition;
#or
push @a, 'fred' while @a < 10;
[download]

And then realising that I need to do something else in the if or while and so instead of restructuring the line to the

if(..) { ....; ....; } or

while( ... ) { ...; ....; }

I do

$j--
, $i++ if $some_condition;
#or
print scalar @a
, push @a, 'fred' while @a < 10;
[download]

This is usually a temporary step while I try something out or when debugging, but I've been bitten enough times by the "comma thing" to recognise the symtoms.