Programmer, graduate student, and gamer. I’m also learning French and love any opportunity to practice :)

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Cake day: June 1st, 2023

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  • You have to be explicit about which module you’re using at all times, even though 99% of the time only one could apply. When the type class resolution is unique, but complicated, there’s no mental overhead for the Haskell programmer but getting all the right modules is a lot of overhead for the OCaml programmer. It also lets us write functions that are polymorphic under a class constraint. In OCaml you have to explicitly take a module argument to do this. If you want to start composing such functions, it gets tedious extremely fast.

    And then even once you’re using a module, you can’t overload a function name. See: + vs +.. Basically modules and type classes solve different problems. You can do some things with modules that you cannot ergonomically do with type classes, for example. create a bit-set representation of sets of integers, and a balanced search tree for sets of other types, and expose that interface uniformly from the same module functor. But Haskell has other ways to achieve that same functionality and more.

    OCaml’s type system cannot replicate the things you can do with Haskell’s higher kinded types, type families, or data kinds at all (except for a fraction of Haskell’s GADTs).


  • Largely reasonable?

    Haskell is not good for systems programming which sums up about 60-70% of that post. Laziness is lovely in theory but many industry uses of Haskell use stricthaskell for all or most of their code, so I certainly agree with that part too.

    Their largest complaint about using Haskell for small non-systems programs seems to be the mental overhead induced by laziness. But for me, for small programs where performance isn’t a huge concern (think Advent of code or a script for daily life) laziness reduces my mental overhead. I think that author is just especially concerned about having a deep understanding of their programs’ performance because of their systems background. I worry about performance when it becomes relevant. Debugging Haskell performance issues is certainly harder than strict languages but still totally doable.

    The lack of type classes or other form of ergonomic overloading in OCaml is easily the single “feature” most responsible for the language never taking off.