[metadata]

> The generated .NET IL is not great. seq turns into an IEnumerable, list is some sort of linked list, I'm pretty sure you'd get pretty terrible performance if you did this.

Functional languages have completely different data structures. What is intuitively fast in C# (arrays) may be terribly slow in FP. For example, Erlang (and hence Elixir) are far slower than C# in single-threaded tasks. But, immutability of data allow for incredible parallelism. F# allows mutability, but the default is immutable data.

I remember quite some time ago, when ASP.NET could handle a few thousand connections, Elixir team achieved 2 million concurrent connections with just a few tweaks to the Elixir codebase.

[1] https://phoenixframework.org/blog/the-road-to-2-million-webs...