+ my $add_remove = $2;
+ my $packages = $3;
+ # if there isn't a package given, assume that we should unset
+ # affects; otherwise default to adding
+ if (not defined $packages or
+ not length $packages) {
+ $packages = '';
+ $add_remove ||= '=';
+ }
+ elsif (not defined $add_remove or
+ not length $add_remove) {
+ $add_remove = '+';
+ }