Hybrid static/dynamic language

Just an idea. I've never heard about something like that: it would be nice to combine static and dynamic features in the single language.

It is obvious there is the possibility to join these features in different ways. But one of the ways seems to me more promising. Namely: the static type part is used in the public API, and leave dynamic elements of the language in the "private" scope of modules* (classes, traits and the like).

Code would look like:

class UsersController
  _userDao = UserDao.instance

  String index(RequestParams params)
    order = params.get 'order'
    users = _userDao.order(order).all 
    format users

  def format(users)
    names = users.join ', '

This approach combines conciseness of dynamic languages with safety of static ones.

* not to be confused with the Hindley–Milner type inference algorithm