## Full example

    class List
      new: (t) =>
        if t then return t

      append: table.insert
      join: table.concat

      map: (f,...) => List [f x,... for x in *self]

      -- apply a function on a list in-place
      apply: (f,...) =>
        for i = 1,#@ do @[i] = f @[i],...
        self

      clone: => @slice 1

      slice: (i1,i2=#@) =>
        -- workaround for MS slice bug
        if i2 < 0 then i2 = #@ + i2 + 1
        List [x for x in *self[i1,i2]]

      extend: (other) =>
        i = #self + 1
        for o in *other
            self[i] = o
            i += 1
        self

      partition: (pred,...) =>
        res = {}
        for x in *@
            k = pred x,...
            if not res[k] then res[k] = List!
            res[k]\append x
        res

      lpartition: (n,npred,...) =>
          res = List[List{} for i = 1,n]
          for x in *@
            k = npred x,...
            if k >= 1 and k <= n
                res[k]\append x
          res

      __concat: (l1,l2) ->
            List.clone(l1)\extend l2

      __tostring: =>
        tmp = @slice(1,10)\apply tostring
        if #@ > 10 then tmp\append '...'
        "["..tmp\join(',').."]"

    -- hack to modify class so its constructor may return a new self
    patch = (klass) -> getmetatable(klass).__call = (cls,...) ->
        self = setmetatable {}, cls.__base
        newself = cls.__init self, ...
        if newself
            self = setmetatable newself, cls.__base
        self

    patch List

    return List