mlsub

> I don’t understand why… Because dynamic typing has its own advantages, which are worthy of experimentation even if you perceive absence of static typing as a weakness. Gradual typing can offer us the benefits of both worlds. > inferred typing is nearly as easy to use while being more robust. Implementing type inference can be fairly trivial if your types are all disjoint. Hindley-Milner type inference is well studied and there's plenty of literature. But as soon as you introduce subtyping, the traditional methods are not sufficient. It's only in the past decade that good solutions have been discovered, notably Dolan & Mycroft's MLsub[1], based on Dolan's Algebriac Subtyping thesis[2], and Parreaux & Chau's MLstruct[3], which uses a boolean algebra approach[4]. Type inference with subtyping is not a solved problem - these developments ar

I once wondered about subtyping[1] too. Looks like there's a possible solution - MLsub[2][3]. But it will require significant amount of work to modify OCaml inference engine to work that way. For now I just use functors for types with the shared fields. It doesn't add too much lines of code either. [1] https://discuss.ocaml.org/t/function-argument-polymorphism/3... [2] https://www.cl.cam.ac.uk/~sd601/papers/mlsub-preprint.pdf [3] https://github.com/stedolan/mlsub