coffeescript permutations

gistfile1.coffee

permute = (array) ->
        buf = []
        return array if array.length == 1
        for element, i in array
          buf.push [element]
          remaining = array.slice()
          remaining.splice(i, 1)
          subPermutations = permute(remaining)
          buf.concat subPermutations
          for sub in subPermutations
            buf.push [element].concat(sub)
        buf