The Ruby examples are unfair.

Ruby intentionally makes parenthesis optional. So `do_something` is `do_something()`.

For the first example,

  - method_as_fun = o.my-method
  - method_as_fun(5) # not reached
  + method_as_fun = o.method(:my_method)
  + method_as_fun.call(5) # or method_as_fun[5]

And for the lexical scope thing,

  def f(x)
    g = ->y {x + y}
    g[2]
  end
  f(2)

Or, explicitly use class variables,

  def f(x)
    @x = x
    def g(y); @x + y; end
    g(2)
  end
  f(2)