Not sure if it's what you're looking for, but here's a all-in-one regex that can do the trick:

$_="keyword=value,option1,option2,option3";

s{^(\w+)
    \s*=\s*
   (.+)$
 }
 {
   @a=split(',',$2)
 }ex
[download]

You now have the keyword in $1, and the values in the array @a

<kbd>--
PerlMonger::Paris(http => 'paris.pm.org');</kbd>