Comment by michaelochurch | Hacker News Reader

Comment by michaelochurch | Hacker News Reader

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OCaml's largest problems, IMO, are:

1. Global interpreter-lock, and the effect that has on the ability to write multi-threaded programs.

2. False negative proof, the same issue Haskell has. The fact that it's "had its chance" to catch on and hasn't done so marks it as a failure (or "not production ready") in the eyes of people who make decisions.

Scala has better odds than Ocaml and Haskell for this reason alone.

3. The perception that there's a lack of libraries relative to, say, the JVM. I say "perception" because Ocaml has bindings to leverage the C libraries. However, it doesn't have the Java libraries, and those are proving to be an important asset even in un-Javay languages like Clojure.

On Scala, since I'm resigned to the fact that it is more likely to win (and find I like the language a lot) the unresolved question in my mind is: is Scala an acceptable ML? I like Scala a lot and I'm leaning toward "Yes", but I haven't worked with Scala on something big enough to have a fully formed opinion there.

4. (Small one.) The name. I would like it just as much if it were called FishGuts, but names matter in adoption. I think Ocaml's a fine name, but I'm weird.

I do not think Scala is an ML. The use of the word acceptable and indeed restricting it to an ML derivative loses the point of what Scala is supposed to be. Scala is supposed to be something different: a successful melding of OOP and functional. And it is the best at that I have seen. It succeeds on this better than the next biggest contender: F#, which is the most acceptable ML, IMO. F# is more typically functional, using the usual Hindley Milner Inference and sharing a core with OCaml but with significant whitespace. So it can be very succinct. Typically functional idioms like algebraic data types, Piping, point free, currying and combinators is more natural to F# than Scala's more OOP way. I prefer F# to Scala but that is merely a subjective preference.

There are a number of things that Scala does naturally that are cumbersome in other languages because of how it manages to meld a powerful combination of orthogonal features. To use Scala as just another functional language is to miss its power. Those who criticize OOP have not used a language that does it right. Abstractly, in a simplified categoric setting, we can consider OOP (objects as coalgebras) and FP (algebraic data types) as duals of each other. A proper unification of the concepts gives something more powerful than either. I think Scala comes the closest. Sure you can be 100% functional in it, or replicate Java but to call it one or the other is to make the same mistake as to say that light is both a wave and a particle and think you understand what that means.

Brilliant

Brilliant synopsis. Thanks!

> is Scala an acceptable ML?

I thought it might be until I tried OCaml, and the difference between type inference that only works on locals and pervasive inference is huge. Also the fact that JVM interop makes it hard to avoid null pointers is a big strike against it.

Still, I agree that the odds are in its favour vs OCaml for things that don't need to be close to the metal.

The global interpreter lock is a large one IMO. One of the huge advantages of type safety is that you can use types to help enforce thread safety rules, but if the interpreter itself can't handle it, that's a huge problem!

Is the global interpreter lock there in AOT compiled code too or just in interpreted code? (IIRC OCaml supports both compiled and interpreted)

Both - it's required for the garbage collector.

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