def.exs

def next_state
  (board, x, y) ->
    cell = cell_at(board, x, y)
    live_count = live_neighbors(board, x, y)
    next_state(cell, live_count)
  end
  ("o", live_count) when live_count in 2..3 -> "o"
  ("o", _) -> "."
  (".", live_count) when live_count === 3 -> "o" 
  (".", _) -> "."
  (_, x, y) when (x < 0 or y < 0) ->  "."

def just_one_arity(x,y) -> IO.puts "hello"
 

# This would internally define both next_state/3 and next_state/2
# Since these are distinctions that the user largely doesn't care about

# Thoughts on referencing functions:
# The syntax here is intentionally an ugly placeholder because it's not important
# This is more about the semantics
$next_state$ # returns an anonymous lambda which dyn-dispatches to all arities, because DWIM
$next_state/2$ # returns a reference to the specific arity definition of next_state
$just_one_arity$ # returns just_one_arity/1 since it's unambiguous