Fl4m3Ph03n1x
Nested modules suggestion?
Background
Recently I decided to do a Mix Task to run some script files in the project. Being my first Mix Task, I followed a tutorial and got the following structure:
defmodule Mix.Tasks.Deploy do
use Mix.Task
@shortdoc "Compiles the app for PROD and starts a Rolling Release."
def run(_) do
#do really awesome stuff here
end
Problem
We are using credo and one of the warnings it gives me is the following:
┃ [D]
Nested modules could be aliased at the top of the invoking module.
┃ lib/mix/tasks/deploy.ex:21:19 #(Mix.Tasks.Deploy.run)
Now, I checked the project dos referring to this error:
And from my understanding I take it I should use a alias somewhere, but I don’t see how.
Question
I can I fix the problem and make the warning go away?
Marked As Solved
Matt
It sounds like you are calling a function like this:
defmodule Mix.Tasks.Deploy do
use Mix.Task
def run(_) do
# doing really cool stuff
# ...
Comeonin.Argon2.hashpwsalt("some password")
# ...
# more cool stuff
end
end
What credo is suggesting is to do something like this:
defmodule Mix.Tasks.Deploy do
use Mix.Task
alias Comeonin.Argon2
def run(_) do
# best programming you have ever seen
# ...
Argon2.hashpwsalt("bestpassword")
# ...
# more cool programming
end
end
So, credo is complaining that you are calling a function with nested module names, Comeonin.Argon2.hashpwsalt/1, for example. It wants you to call a function with a singular module name, like Argon2.hashpwsalt/1. So you can use alias for this purpose. The cool think about alias is that it is lexically scoped. This means you can use it within a function 
if you need.
Also Liked
axelson
Although do note that the “[D] 
” part of the “warning” indicates that is is a very low severity “issue”, really more of a suggestion. I don’t think it’s idiomatic Elixir code to alias every single module you reference. In fact I tend to only alias modules that are used very often in the module, leaving a full module reference to indicate that longer module reference is not used/tied as deeply with the rest of the containing module (sorry this is a little hard to follow).
Matt
I think your reply is meant for @ Fl4m3Ph03n1x?
I do the same, I actually rarely use alias. In fact, I tend not to like using alias often, because I like to know the origin of the functions I am calling. Right or wrong, that is just personal preference on my part though.
OvermindDL1
I alias out parts that are ‘obvious’, like the main namespace at the very least, sometimes down to the specific function call (import) if perfectly obvious, otherwise I keep a name mapping or 2 or 3 worth of dots.
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