macros.ex

defmodule MacroFun do

  defmacro a(str, do: block) do
    quote do
      res = [a: unquote(str)]
      unquote(block)
      res
    end
  end

  defmacro b(str) do
    quote do
      res ++ [b: unquote(str)]
    end
  end

  def c(str) do
  end

end

defmodule Run do
  import MacroFun

  def run do
    result = a("hello") do
      b("bleh")
      c("blah")
    end
    IO.inspect result
  end
end

Run.run

# Desired result: [a: "hello", b: "bleh", c: "blah"]