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Comment by anuragsoni | Hacker News Reader

> I find the `ref` syntax of SML much nicer to use than the mutable record syntax in Ocaml.

Maybe I'm missing something in SML, but OCaml has `ref` as well and it works just like SML's?

  let x = ref 0
  x := 12
  print_int !x

> SML strings are immutable which lends itself to a lot of potential optimizations (and there's always byte arrays if you actually need to mutate).

OCaml's strings are also immutable. They have been immutable by default since 2017 and prior to that one could opt into this behavior via a compiler flag.

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You are correct that Ocaml has a ref type (though I believe it is actually a special case of a mutable record with one field). Most stuff I've run into uses mutable records more than refs (granted, I'm hardly deep into the Ocaml way of doing things). There is a small difference between an immutable record of which one property is a reference to changing data and a mutable record where the record itself changes. I prefer the first though I realize this is mostly preference.

2017 was just 3 years ago. Loads of Ocaml stuff rely on versions much, much older than that. In any case, the idea of outright changing a formerly mutable structure to an immutable one would be unthinkable in most languages due to all the breakages it is likely to cause.

> You are correct that Ocaml has a ref type (though I believe it is actually a special case of a mutable record with one field). > There is a small difference between an immutable record of which one property is a reference to changing data and a mutable record where the record itself changes. I prefer the first though I realize this is mostly preference.

In OCaml ref is defined as

  type nonrec 'a ref = 'a ref = { mutable contents : 'a }

so it is an immutable record which contains one item which is mutable.

> In any case, the idea of outright changing a formerly mutable structure to an immutable one would be unthinkable in most languages due to all the breakages it is likely to cause.

I agree with you. I started using OCaml in 2018 but I believe many linux distributions stayed on OCaml 4.05 (the release before safe-string was default) for a while because of breakages.

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