Great job, thank you for taking the time to do it. I found guard functions to macros and destructing extremely helpful (life changing?)!
LawJolla
blackode
Qqwy
TypeCheck Core Team
Interesting article!
Here are some important notes that you might want to include to make the different points more complete:
-
- Strings to module names: You use
Module.concatin your article, but in 99/100 cases you’ll want to useModule.safe_concatinstead: Atoms are not garbage collected, which means that when different atoms are made (that did not exist before), for instance when them somehow depending on user input, you open up your application to an easy DDoS attack.
- Strings to module names: You use
-
- I would like to add here that it is almost always a bad idea to pipe an anonymous function. It is a clear indication that you have a bit of code that could be split off in its own, named function using
defordefpthat does what you want.
- I would like to add here that it is almost always a bad idea to pipe an anonymous function. It is a clear indication that you have a bit of code that could be split off in its own, named function using
-
- Note that it only removes the first occurrence of every element in the second list. Note also that it is rather slow to use
--. If you frequently need to remove elements from a collection, you properly would want to use either a Set or a Map instead.
- Note that it only removes the first occurrence of every element in the second list. Note also that it is rather slow to use
Qqwy
TypeCheck Core Team
You might want to add to 7) that if you want keywords to be able to passed in any order, you should accept any list in your function head, and then use Keyword.get inside the function instead:
defmodule User do
def user(options) do
name = Keyword.get(options, :user)
age = Keyword.get(options, :age)
"name: #{name}-- age: #{age}"
end
end
This also allows you to specify useful default values for keywords that are not included when the function is called.
And for 8) Note that there is Map.get/3 as well, which allows you to retrieve a value from a map with a default when it does not exist.
blackode
blackode
gregvaughn
I encourage a bit of clarification to #9. You said
Always avoid using atoms as keys
Atom keys are great! If you have a fixed number of them defined statically in your code, you are in no danger. What you should not do is convert user supplied input into atoms without sanitizing them first because it can lead to out of memory. You should also be cautious if you create dynamic atoms in your code. If you have a fixed upper limit to how many you will create, you are fine, but if they can grow without bound, then you risk out of memory.
blackode
Firstly, thanks for your time and review on article. That is really something to me. 
Thanks for more clarification on the atoms as keys in map. I agree with the statement
"Atom keys are great! If you have a fixed number of them defined statically in your code, "
I just added more clarification as you suggested and I added above statement in article.
Thanks for educating.
blackode
This article explains about Elixir Module Deployment across multiple nodes from the scratch. Here we go with deep understanding of things like Node Creation, Establishing Node Connection and Deploying Modules across multiple Nodes.
https://medium.com/@blackode/deploying-elixir-modules-different-nodes-6c9cc17d3b97
Happy Coding !!
davearonson
As a general rule, don’t do ANYTHING with user supplied input without sanitizing it first. 