How to create a dynamic function name using Elixir macro?

Question

I want to create a function names dynamically. I wrote this macro

defmacro generate_dynamic(name) do
  quote do 
    def add_(unquote(name)) do
    end
  end
end

And I used it like this:

defmodule AnotherModule do
  generate_dynamic :animal
end

Now, I only get AnotherModule.add_ function defined, whereas I expect AnotherModule.add_animal function.

question from:https://stackoverflow.com/questions/30498528/how-to-create-a-dynamic-function-name-using-elixir-macro

Answer 1

To achieve this, you can prepend :add_ to the name before unquoting. Also, the parentheses after the method name in this case are required to prevent ambiguities. This should do the trick:

defmacro generate_dynamic(name) do
  quote do 
    def unquote(:"add_#{name}")() do
      # ...
    end
  end
end