module Fibo
  a = 5 + foo
  bar( b , a , r)
end

-- -- --
s(:list,  [s(:module,  "Fibo",  [s(:assign, 
  s(:name,  "a"), 
  s(:operator,  "+", 
    s(:int,  5), 
    s(:name,  "foo"))), s(:call, 
  s(:name,  "bar"), 
  s(:arguments, 
    s(:name,  "b"), 
    s(:name,  "a"), 
    s(:name,  "r")))])])