Compiler Reminders
6 comments
·April 27, 2025JonChesterfield
fredrikholm
They make it near impossible to extend from the outside.
I can pass a Reader interface to your function, but I cannot (easily) add a
> | UnusualProtocol(Socket)
as a third party consumer.
Other than that, sum types are the better abstraction. With exhaustive first class pattern matching (eg. with proper matching on destructuring), nothing comes close in terms of ergonomics.
hermanradtke
That is a feature. Compose instead of extending.
Yoric
OCaml has extensible sum types. They work very nicely for some ranges of problems.
gitroom
Tbh, missing those checks in other languages bugs me so much - it's like why leave me hanging?
swiftcoder
Elm <-> Rust
Best buds on this front
Exhaustive compile time checking of dispatch statements is a wonderful thing, sorely missing from the languages that decided "sum types" are a bit weird and niche.