That's when the $& aka line break identifier comes in handy:

var %w = /word1|word2|word3|word4|word5|$&
$+ word6|word 7|word8|Word9|...|...|...|...|...|$&
$+ .../iS
if ($regex($1-,%w)) {

this allows you to break up a long line of code into the next one and so on...

The downside is that $& cannot apply to on text regex. ^^ I'm fairly certain that you can do it through the $regex() without using a temp variable as shown, but I have yet to give it a whirl.