The macro mechanism in Elixir is not only an interesting metaprogramming feature - in fact, it is at the language's very core. And the more awesome fact is that, using macros, you can override the algorithm of defining functions itself!
So you don’t know what’s the type of struct you’re passing somewhere? Maybe it can be one of few types and you have to distinguish them? Or any other reason… But it’s about checking the struct type. Just use one of the coolest Elixir features - pattern matching!
Hey! Have you ever wondered about tests running inside the IEx shell? For a long time, I was convinced that it’s not really possible. And as it turns out - that’s not really straightforward. You won’t easily find information about that in the documentation.
Sometimes you need to do some database operations at once. A simple example: User-A transfers money to User-B. Updating just one balance at the time creates a risk of data desynchronization. What if the first DB operation goes well but updating the second user’s data fails? Sounds like a hard to catch vulnerability.