owo Pass-by-reference test

owo Swap two variables.
functio swap(left, right) {
   tmp dim left;
   right =: left;
   tmp =: right;
}

foo dim /*hello*/;
bar dim /*world*/;

swap(foo, bar);

unless (foo = /*world*/) {
   /*FAILED*/ print;
   /*foo should be 'world', is actually:*/ print;
   foo print;
}

unless (foo ain't /*world*/) {
   /*OK*/ print;
}