Elixir macros and bind_quoted

Question

I have a macro that defines a module like so.

defmodule Bar do
  def bar do
    IO.puts \"I am #{inspect __MODULE__}\"
  end
end

defmodule MacroFun do

  defmac         


        

Answer 1

With this code you will see the correct values used to create the modules:

require Logger

defmodule Bar do
  def bar do
    IO.puts "I am #{inspect __MODULE__}"
  end
end

defmodule MacroFun do

  defmacro define_module(name) do
    quote do
      Logger.debug("#{inspect unquote(name)}")
      defmodule unquote(name) do
        import Bar
        Logger.debug("#{inspect unquote(name)}")
        def foo do
          bar
          IO.puts "I am #{inspect __MODULE__}"
        end
      end
    end
  end

  defmacro define_module2(name) do
    quote bind_quoted: [name: name] do
      defmodule name do
        import Bar
        Logger.debug("#{inspect name}")
        def foo do
          bar
          IO.puts "I am #{inspect __MODULE__}"
        end
      end
    end
  end
end

defmodule Runner do
  require MacroFun

  def run do
    MacroFun.define_module Foo
    Foo.foo
  end
  def run2 do
    MacroFun.define_module2 Foo2
    Foo2.foo
  end

end

Runner.run
Runner.run2

Output:

[warn]  Foo
[warn]  Runner.Foo
I am Bar
I am Runner.Foo

[warn]  Foo2
I am Bar
I am Foo2