Why I think the dot is not a problem in Elixir

adolfont

Adolfo Neto

Posted on April 27, 2022

Why I think the dot is not a problem in Elixir

Update! Read this beautiful post by José Valim: Why the dot (when calling anonymous functions)?

The Elixir community knows that, in Elixir, when you define an anonymous function and assign it to a variable, you have to use a dot (.) to call it:

iex(1)> double = fn x -> x*2 end
#Function<44.65746770/1 in :erl_eval.expr/5>
iex(2)> double.(3)
6
iex(3)>
Enter fullscreen mode Exit fullscreen mode

This doesn't happen in Erlang:

1> Double = fun(X) -> X*2 end.
#Fun<erl_eval.44.65746770>
2> Double(3).
6
3>
Enter fullscreen mode Exit fullscreen mode

You don't have to put a dot between Double and (3) in Erlang.

But you have to put a dot at the end of each line.

The late Joe Armstrong, one of the creators of Erlang, wrote in 2013, when he spent "A Week with Elixir," more specifically in the section "Funs have an extra dot in the name":

In school I learned to call functions by writing f(10) not f.(10) – this is “really” a function with a name like Shell.f(10) (it’s a function defined in the shell) The shell part is implicit so it should just be called f(10).
If you leave it like this expect to spend the next twenty years of your life explaining why. Expect thousands of mails in hundreds of forums.

I believe this didn't happen. One or other person complains here and there, but not "thousands".

Why? My opinion is that Elixir developers usually don't assign an anonymous function to a variable. That's why this is not a big problem. Am I right?

💖 💪 🙅 🚩
adolfont
Adolfo Neto

Posted on April 27, 2022

Join Our Newsletter. No Spam, Only the good stuff.

Sign up to receive the latest update from our blog.

Related