###

Operators
---------

  CoffeScript           JavaScript
  == is                 ===
  != isnt               !==
  not                   !
  and                   &&
  or                    ||
  true yes on           true
  false no off          false

###

paid = coffee = pour = ->

if paid() and coffee() is on then pour()

addCaffeine = Decaf = ->

addCaffeine() if not Decaf()
addCaffeine() unless Decaf()

# Combined range checks
level = 4
if 2 < level < 5
  alert "In range"

# Functional switch.
message = switch cupsOfCoffee
  when 0 then 'Asleep'
  when 1 then 'Eyes open'
  when 2 then 'Buzzed'
  else 'Dangerous'

# Existential check: not undefined and not null.
if cupsOfCoffee?
  alert('Exists')
alert 'Exists' if cupsOfCoffee?

# Not strictly identical to the two shorter forms below.
if not cupsOfCoffee?
  cupsOfCoffee = 0

cupsOfCoffee = 0 unless cupsOfCoffee?
cupsOfCoffee ?= 0

coffeePot?.brew()

# Like Ruby "try"
vehicle.start_engine?().shift_gear?().crank?().press_gas?()