"Make it work, then make it beautiful, then if you really, really have to, make it fast. 90 percent of the time, if you make it beautiful, it will already be fast. So really, just make it beautiful!"
– Joe Armstrong
– Joe Armstrong
You have a set of tools with comparable degrees of features and productivity*, but one of them comes at a steep performance cost, perhaps you might want to pick the one that is snappier and easier to use?
* Though one could argue F# offers more in regular niceties at the cost of not having distributed framework built-in, requiring you to reach for Akka. I certainly find F# significantly easier to read and write than Erlang.
Run into something slow? Replace that small bit with a Rust NIF and move on with your life.
(you have to maintain separate toolchain and exports in Rust, to achieve this, and complex types cannot be easily exported/imported - it is subject to limitations of C ABI, and FFI is not free either, even when as cheap as it gets - .NET has that with P/Invoke yet still it is a deoptimization in data-intensive algorithms, which benefit from being rewritten in C#/F#)