assembly level closure implementation (inspired by upvalues)

closure.py

def f1():
  x = 1
  def f2():
    y = 2
    def f3():
      return x+y
    return f3
  return f2
  
f1:
  x = new Integer(1)
  f2 = ([(&x, null)], f1$f2)
  ...
  f2[0][0][1] = new (void*)
  *f2[0][0][1] = x
  f2[0][0][0] = &f2[0][0][1]
  
f1$f2:
  y = new Integer(2)
  f3 = ([arg0[0], (&y, null)], f1$f2$f3) # arg0 is the closure list
  ...
  f3[0][1][1] = new (void*)
  *f3[0][1][1] = y
  f3[0][1][0] = &f3[0][1][1]
  return f3
  
f1$f2$f3:
  return *arg0[0][0] + *arg0[1][0]