Elixir into Erlang transformation

Question

I want to see what happens when elixir gets transformed into beam files. Is there any way to print in console or in a file how it is translated? I want to know what would th

Answer 1

This probably should be more of a comment to @Dogbert’s answer above, but I would post it as a separate answer for the sake of formatting.

One does not need to create .ex files and invoke the compiler on them to produce beams:

{:module, _, bytecode, _} =
  defmodule Elixir.Test do
    def t1(a), do: a
    def t1(a, b \\ 2), do: a + b
  end
# File.write!("Elixir.Test.beam", bytecode)

now you might have had a beam file written (we have it stored in the bytecode variable by the way.)

NB: beam_lib:chunks/2 works if and only the beam contains unencrypted debug information (elixir beams by default do.)

Also, you don’t need to write decompiled erlang code, you might simply pass a binary there, directly in Elixir:

:beam_lib.chunks(bytecode, [:abstract_code])

To extract the code itself:

{:ok,{_,[abstract_code: {_, code}]}} = 
   bytecode |> :beam_lib.chunks([:abstract_code])

Now code contains the code, it should be enough to examine it, but you still are free to use erlang build-ins:

code |> :erl_syntax.form_list

or:

code |> :erl_syntax.form_list |> :erl_prettypr.format

The latter will give you the binary charlist, containing erlang code, exactly as in @Dogbert’s answer. Use IO.puts to output it.