__using__ macro with option

[Eiji]

@mruoss

But your example with the 10 features only works because a quoted list of atoms is still a list of atoms, right? If for some stupid reason I decide to pass enabled_features: [String.to_atom("my_frature")], it would not work?

If it’s stupid, but it works then it’s no stupid!

I have used atom as it’s best for what I called feature_name as those in apply_feature/1 are known at compile-time. You can use strings, integers and every other data that you can write pattern-matching for.

Also take a look at example below:

some_macro(["a", "b", "c"])
# param value in macro
# ["a", "b", "c"]

some_macro(~w[a b c])
# param value in macro
# {:sigil_w, [delimiter: "[", context: Elixir, imports: [{2, Kernel}]],
#  [{:<<>>, [], ["a b c"]}, []]}

some_macro(~w[a b c])
# value of `Macro.expand(param, __CALLER__)`
# ["a b c"]

If you want to call String.to_atom/1 inside macro then:

1. You can call Enum.map(list, &String.to_atom/1) as long as you require list of atoms passed as raw list or sigil (see above example)
2. In function definition String.to_atom/1 call needs to be passed inside unquote/1 call.
3. Inside module and function block you can use String.to_atom/1 call as well inside unquote/1 call as outside unquote/1 call.

Hope that helps.