Dynamic list of arguments in function definition

[joaquimadraz]

Hey @danielberkompas,

I was trying define a function that includes an argument that is being destructed like this:

  def some_fn(params = d%{name, email}, person \\ Person) do
    params
  end

And I got this error a compile error: expected key-value pairs in a map, got: name.

After a while digging into the code, I found out that if I define a new macro:

  defmacro d({:%{}, context, args}, person) do

..the compile error is gone.

I'm still trying to get my head around meta programming in Elixir and this is confusing for me.
Why is destructure handling other arguments?

Thanks 😃

[ssboisen]

Hi @joaquimadraz

You should wrap your use of d in parentheses in this case

def some_fn(params = d(%{name, email}), person \\ Person) do
  params
end

[muhifauzan]

Hi @joaquimadraz, It's appear that the macro behave differently on matching operator. As @ssboisen suggest, you need to use parentheses in matching operator. Maybe someone more expert can explain why.

[joaquimadraz]

@ssboisen Cool, that solves the problem. Thanks!