alt Hacker News>Haskell (and OCaml etc) give you both straightjackets..
Haskell's thing with purity and IO does not feel like that. In fact Haskell does it right (IO type is reflected in type). And rust messed it up ("safety" does not show up in types).
You want a global mutable thing in Haskell? just use something like an `IORef` and that is it. It does not involve any complicated type magic. But mutations to it will only happen in IO, and thus will be reflected in types. That is how you do it. That is how it does not feel like a straight jacket.
Haskell as a language is tiny. But Rust is really huge, with endless behavior and expectation to keep in mind, for some some idea of safety that only matter for a small fraction of the programs.
And that I why I find that comment very funny. Always using rust is like always wearing something that constrains you greatly for some idea of "safety" even when it does not really matter. That is insane..
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When I started learning Haskell, it did feel like coding with a straightjacket.
> "safety" does not show up in types
It does in rust. An `unsafe fn()` is a different type than a (implicitly safe by the lack of keyword) `fn()`.
The difference is that unsafe fn's can be encapsulated in safe wrappers, where as IO functions sort of fundamentally can't be encapsulated in non-IO wrappers. This makes the IO tagged type signatures viral throughout your program (and as a result annoying), while the safety tagged type signatures are things you only have to think about if you're touching the non-encapsulated unsafe code yourself.