The naming convention docs explain here. Generally it’s what you say but they also give the example of alias! and var! from macros whose variants don’t return tuples (it is, after all, basically just a much better alternative to only matching on the :ok case). It also points out that there are cases where there is a bang variant with no non-bang variant. For those who are familiar with Ruby, this is differs says if you have a bang you also have a non-bang (again, just convention). Though in Ruby it’s also often used to signify the mutation version of a method and many methods only mutate and just go with the non-bang (eg, Array#delete). I always found this a bit confusing.
Getting back on track, though, in all cases in Elixir’s stdlib, ! always signify’s something’s going to raise. As much as I like to personally stick to this convention, I don’t think it’s a huge deal when people want to stray from it. I think it can add a certain expressiveness in some domains. In libraries it’s certainly very iffy but I still believe it’s up to the author. Just my two cents, of course.
What is going on here?