为了证明这种方式是可以用的, 我尝试写了个模块:
https://github.com/jiyinyiyong/proto-scope

 human = proto.as
  init: -> @name = 'human race'
  give_name: (@name) ->
  introduce: -> console.log "this is #{@name}"

tom = human.new()
tom.introduce() # => "this is human race"

man = human.as
  speak: ->
    print 'speaks by', @name
dan = man.new()
dan.give_name 'Dan'
dan.introduce() # => "this is Dan"
dan.speak() # => "speaks by Dan"

从功能上说, proto 是可行的, 在 Node 环境里也是正常能跑的,
但是为什么没人在实际使用当中这样用呢?