Can someone enlighten me on this piece of code?

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8

Eh, not really like assembler, it is the very definition of AST. Elixir’s AST. :slight_smile:

The compilation process goes: Elixir → Elixir’s AST (what quote gives you) → Erlang (Abstract Format, basically it’s AST) → Core Erlang → BEAM
With a variety of translators along the way too. :slight_smile:

Basically take this Elixir:

defmodule :tester do

  def hi, do: "there"

end

To this Elixir AST:

{:defmodule, [context: Elixir, import: Kernel],
 [:tester,
  [do: {:def, [context: Elixir, import: Kernel],
    [{:hi, [context: Elixir], Elixir}, [do: "there"]]}]]}

To this Erlang:

-module(tester).
-export([hi/0]).
hi() -> <<"there">>.

To this Core Erlang:

module 'tester' ['hi'/0,
                 'module_info'/0,
                 'module_info'/1]
    attributes []
'hi'/0 =
    %% Line 3
    fun () ->
        #{#<116>(8,1,'integer',['unsigned'|['big']]),
          #<104>(8,1,'integer',['unsigned'|['big']]),
          #<101>(8,1,'integer',['unsigned'|['big']]),
          #<114>(8,1,'integer',['unsigned'|['big']]),
          #<101>(8,1,'integer',['unsigned'|['big']])}#
'module_info'/0 =
    fun () ->
        call 'erlang':'get_module_info'
            ('tester')
'module_info'/1 =
    fun (_cor0) ->
        call 'erlang':'get_module_info'
            ('tester', _cor0)

To this BEAM Assembly:

00007F031584F908: i_func_info_IaaI 0 tester hi 0
00007F031584F930: move_return_c <<"there">>

00007F031584F940: i_func_info_IaaI 0 tester module_info 0
00007F031584F968: move_cr tester r(0)
00007F031584F978: allocate_tt 0 1
00007F031584F988: call_bif_e erlang:get_module_info/1
00007F031584F998: deallocate_return_Q 0

00007F031584F9A8: i_func_info_IaaI 0 tester module_info 1
00007F031584F9D0: move_rx r(0) x(1)
00007F031584F9E0: move_cr tester r(0)
00007F031584F9F0: allocate_tt 0 2
00007F031584FA00: call_bif_e erlang:get_module_info/2
00007F031584FA10: deallocate_return_Q 0

And that is what is loaded by the VM.

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