Something

}
on *:text:!setpc*:#:{
  if ($nick isop $chan) {
    set %world $2-
    .notice $nick The new PC world is: %world
  }
  else {
    .notice $nick You cant set a new Pc World, you have to be Op(Operator, @)
  }
}
on *:text:!unsetpc*:#:{
  if ($nick isop $chan) {
    unset %world
    .notice $nick The PC World has been unseted, to set a new one write: !setpc WORLD.
  }
  else {
    .notice $nick To do this you have to be Op(Operator, @)
  }
}