$a = $in{'a'};
$b = $in{'b'};
$c = $in{'c'};
$d = $in{'d'};
.
.
.

##</code><code>##

$fieldList = $in{'fieldList'};
@fieldList = split(",",$fieldList);
foreach $field(@fieldList){
     $$field = $in{'$field'};
}