shuffle.coffee

# fisher yates shuffle algorithm
# http://en.wikipedia.org/wiki/Fisher–Yates_shuffle
  Array::shuffle = ->
    copy = @copy()
    i = @length
    while --i
      j = Math.floor(Math.random() * (i + 1))
      temp = copy[i]
      copy[i] = copy[j]
      copy[j] = temp
    return copy