I’ve seen -> and <- used in Elixir books and articles, but I have not found a clear explanation to what they are called, and when they should be used.
Generator Example: for n <- 1..4, do: n * n
In an anonymous function, -> makes syntactical sense, but I don’t understand all of the use cases of <-
Sorry for the noob question 
but I’m still learning Elixir 
