Normalize the AST before sending it to the go driver

[Serabe]

We need to, for lack of a better word, normalize the AST before sending it to the go driver.

I'll try to summarize what I've learned about the AST.

There are some types whose AST representation are themselves:

• Atoms (:atom)
• Integers (123)
• Float (3.14)
• Lists ([1,2,3])
• Strings ("string")
• 2-Tuples ({:this, :tuple}, but {:not, :this, :tuple})

The rest is represented as a 3-tuple with the following pattern:

{
  :operator, # function name as an atom
  [], # metadata (I think this is a keywords http://elixir-lang.org/getting-started/keywords-and-maps.html
  [] # list of arguments
}

Some examples:

quote do: Enum
{:__aliases__, [alias: false], [:Enum]}

Learn about SpecialForms.

quote do: Module.Submodule.fun 1
{
  {
    :.,
    [],
    [
      {:__aliases__, [alias: false], [:Module, :Submodule]},
      :fun
    ]
  },
  [],
  [1]
}

The tail argument for the :. operator is always an atom.

quote do: fun(1,2)
{:fun, [], [1, 2]}

quote do: fun([1,2])
{:fun, [], [[1, 2]]}

quote do: MyModule.fun({:ok, 1, 2}, default: 4)
{{:., [], [{:__aliases__, [alias: false], [:MyModule]}, :fun]}, [],
 [{:{}, [], [:ok, 1, 2]}, [default: 4]]}

[default: 4] is a keywords and cannot be treated like a list.

quote do: def fun, do: 1
{:def, [context: Elixir, import: Kernel],  [{:fun, [context: Elixir], Elixir}, [do: 1]]}

Look that block params in function definition seems no different than other keywords.

This is what I've learnt so far.