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“信息/1”记录在哪里?

elixir

toraritte · 技术社区 · 6 年前

找到这个了吗 Ecto.Repo.Supervisor 我想知道其他的选择 __info__/1 记录如下:

  def compile_config(repo, opts) do
  # (...)
    behaviours =
      for {:behaviour, behaviours} <- adapter.__info__(:attributes),
          behaviour <- behaviours,
          do: behaviour

  # (...)
  end

The Module documentation 只是提到了这一点

将引发错误,因为它超出了检查运行时的范围数据。大多数运行时数据都可以通过附加到每个编译模块的函数。

1 回复 | 直到 6 年前

toraritte 6 年前

我在里面找到的 Module 's source

 @doc """
  Provides runtime information about functions and macros defined by the
  module, etc.
  Each module gets an `__info__/1` function when it's compiled. The function
  takes one of the following atoms:
    * `:functions` - keyword list of public functions along with their arities
    * `:macros` - keyword list of public macros along with their arities
    * `:module` - the module atom name
    * `:md5` - the MD5 of the module
    * `:compile` - a list with compiler metadata
    * `:attributes` - a list with all persisted attributes
  """
  def __info__(kind)

:deprecated -显示模块中前缀为的弃用函数 @deprecated 属性(包含在 1.7.0-rc.0 )

尝试上述方法 behaviour = 凤凰城项目中的上述片段:

$ iex -S mix phx.server

iex(3)> Ecto.Adapters.Postgres.__info__(:attributes)
[
  vsn: [168581197275628950002173003256895919063],
  behaviour: [Ecto.Adapter],
  behaviour: [Ecto.Adapter.Migration],
  behaviour: [Ecto.Adapter.Queryable],
  behaviour: [Ecto.Adapter.Schema],
  behaviour: [Ecto.Adapter.Transaction],
  behaviour: [Ecto.Adapter.Storage],
  behaviour: [Ecto.Adapter.Structure]
]

iex(4)> for {:behaviour, behaviours} <- 
...(4)>     Ecto.Adapters.Postgres.__info__(:attributes),
...(4)>   behaviour <- behaviours, 
...(4)>   do: behaviour
[Ecto.Adapter, Ecto.Adapter.Migration, Ecto.Adapter.Queryable,
 Ecto.Adapter.Schema, Ecto.Adapter.Transaction, Ecto.Adapter.Storage,
 Ecto.Adapter.Structure]

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