I apologize if this has been discussed before, and I’m sure it probably has been, but it’s very hard to search for. I’ve been putting off asking about it for a while now, though, so I’m curious about this pattern:

_ = SomeMod.some_func("some_arg")

I’ve seen this in the docs before but the most prominent example I know of is the first two lines of the first function definition in Phoenix, here. If you aren’t a fan of clicking it looks like this:

# Warm up caches
_ = Phoenix.Template.engines()
_ = Phoenix.Template.format_encoder("index.html")

The best explanation I can come up with is that it’s signalling a side-effect. Is that it?? If it is, I find that kind of really nice, although perhaps at the same time it’s warmed me up a bit to typing (in Elixir) as it took me way to long to figure that out, lol.

But really, it is that it? If not, what’s up with this?