def beers(n)
| 0 => "no more bottles of beer"
| 1 => "1 more bottle of beer"
| _ => $"$n bottles of beer"
def onTheWall = n => $"$(beers(n)) on the wall, $(beers(n)).\n"
def passAround(n)
| 0 => $"Go to the store and buy some more, $(beers(99)) on the wall.\n"
| _ => $"Take one down and pass it around, $(beers(n-1)) on the wall.\n"