module Hamster::Enumerable

def join(separator = $,)

separator, which is normally `nil`.
`separator`. By default, the `separator` is `$,`, the global default string
Convert all the elements into strings and join them together, separated by 
def join(separator = $,)
  result = ""
  if separator
    each_with_index { |obj, i| result << separator if i > 0; result << obj.to_s }
  else
    each { |obj| result << obj.to_s }
  end
  result
end