I personally hate it when people post clickbait titles and take their sweet time getting to the point, so let’s do this first:
TL;DR: Some Elixir string operations, most notably String.at/2 work in linear time, as opposed to constant time, like the intuition might suggest. This is because the String module is UTF-8 aware. UTF-8 encodes characters outside of ASCII with more than one byte, so in order to find the n-th character in a string you need to process it from the beginning, you can’t just use an offset in memory.
Below is a reprint of the article I wrote for the Rekki Medium page.
REKKI builds tools that help people along the restaurant supply chain do their jobs better.
We have a free mobile app that lets restaurants order and chat with suppliers, and a web-based tool for suppliers that helps them process orders, manage product codes and catalogues, and communicate more easily with their customers. The majority of REKKI’s backend is written in Elixir, working hand in hand with services written in Go and Node. The Elixir services handle most of what the user sees in the app like the real-time communication with the supplier and the status of the orders.
Earlier this year I gave a talk at Code BEAM STO about a proposed solution to the ever more real risk of hidden malicious code in our library dependencies. You can watch the whole thing here:
UPDATE: I have since dropped active development of the Hoplon project, but I hope something like it will become reality when the tech community is ready for it :)
I’d argue Elixir has relatively few gotchas. It’s a simple and consistent language and when you first learn it there’s only a few things that are genuinely counter-intuitive and catch you by surprise.
One of the examples could be the difference between binaries and charlists and why iex sometimes seems to do weird things to your lists:
iex> l = [19, 7, 16, 119, 97, 116] [19, 7, 16, 119, 97, 116] iex> Enum.drop(l, 1) [7, 16, 119, 97, 116] iex> Enum.drop(l, 2) [16, 119, 97, 116] iex> Enum.drop(l, 3) 'wat' One of the other ones comes when you start working with atoms and get a little too trigger-happy with them. What you could hear from your more experienced teammates is something like this:
Earlier this year I presented my latest project - Hoplon - at the London Elixir meetup. I’m thinking of putting some more work into it over Christmas, so I figured I might gather the materials about it in one place:
Hoplon is an Elixir developer tool that helps you validate your dependencies contain no hidden malicious code. Motivated by horror stories from the JavaScript community such as this hypothetical one and this very real one.
