Is there something about purely functional languages that make them attractive to blockchain applications? I remember a post on here a little while ago complaining about Haskell adoption in industry was being mostly led by cryptocurrencies.

One person might say that the common factor is not being frightened of doing something challenging and unconventional that allows you to achieve extraordinary things.

Another might say it was a weakness for snake oil.

You have high-stake operations in relatively small code base, so you better pick a language and tools compatible with formal verification or even supporting it natively.

Just to make it clear, OCaml is not purely functional.

Oh sorry, not sure why I thought it was.

Yeah, it most likely is not. I mix imperative, OOP, and functional all the time. Parts of my codebase that has to do with algorithms are written using imperative style, the "public API" is OOP (class, object, methods) which makes the use of my library a breeze, and the rest is functional.

To give you an example of how you would use some crypto-related library that implemented its API (?) in OOP:

  let x = new Foo.bar in
  x#absorb a;
  x#squeeze b;
  x#reset

Or take a look at: https://github.com/xavierleroy/cryptokit/blob/master/src/cry...

This (this entire file) is a great example, too!