长生不老药转变为Erlang [英] Elixir into Erlang transformation

问题描述

我想看看当长生不老药转化为射线文件时会发生什么。有什么方法可以在控制台或文件中进行打印？我想知道这个模块在erlang中是什么样子。

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 this module look like in erlang.

我在考虑是否有elixir调试模式，该调试模式会输出上述任何内容。

I was thinking if there is a debug mode of elixir, which would output any of the above.

更具体地说，我有这个示例：

More specifically I have this example:

defmodule Test do
    def t1(a), do: a
    def t1(a, b \\ 2), do: a + b
end

上面的代码会引发警告，考虑到我所做的事情，这是非常重要的。基本上，我想了解更多情况。

The above code raises a warning, which is understanable considering what I've done. Basically I want to understand a bit more what's happening.

推荐答案

首先，您需要将Elixir模块编译为.beam文件。 ：

First, you need to compile the Elixir module to a .beam file:

$ cat test.ex
defmodule Test do
    def t1(a), do: a
    def t1(a, b \\ 2), do: a + b
end
$ elixirc test.ex
warning: this clause cannot match because a previous clause at line 2 always matches
  test.ex:3

这将生成 Elixir.Test.beam 。然后，您可以使用以下escript将此.beam反编译为Erlang源代码（我之前在Stackoverflow上的某个答案中复制了此代码。不幸的是，我似乎无法找到确切的源代码，但是此代码在很多答案中都包括< a href = https://stackoverflow.com/a/1069185/320615>这。）：

This will generate Elixir.Test.beam. Then, you can decompile this .beam to Erlang source using the following escript (I copied this from some answer here on Stackoverflow a while ago. Unfortunately I can't seem to locate the exact source but this code is in many answers here including this one.):

$ cat decompile.erl
#!/usr/bin/env escript

main([BeamFile]) ->
  {ok,{_,[{abstract_code,{_,AC}}]}} = beam_lib:chunks(BeamFile,[abstract_code]),
  io:fwrite("~s~n", [erl_prettypr:format(erl_syntax:form_list(AC))]).

然后运行它：

$ escript decompile.erl Elixir.Test.beam
-compile(no_auto_import).

-file("test.ex", 1).

-module('Elixir.Test').

-export(['__info__'/1, t1/1, t1/2]).

-spec '__info__'(attributes | compile | exports |
         functions | macros | md5 | module |
         native_addresses) -> atom() |
                      [{atom(), any()} |
                       {atom(), byte(), integer()}].

'__info__'(functions) -> [{t1, 1}, {t1, 2}];
'__info__'(macros) -> [];
'__info__'(info) ->
    erlang:get_module_info('Elixir.Test', info).

t1(a@1) -> a@1;
t1(x0@1) -> t1(x0@1, 2).

t1(a@1, b@1) -> a@1 + b@1.

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