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0 pointsmrkgnao8y ago0 comments

Rust uses Hindley-Milner type inference. OCaml uses Hindley-Milner. Swift apparently uses a variant of the system with more features.

None of these make use of monads or anything rooted in category theory.

https://en.wikipedia.org/wiki/Hindley%E2%80%93Milner_type_sy...

HM is a type system that also gives you an algorithm to infer types without having to do the "List<Integer> foo = new ArrayList<Integer>()" dance from languages without type inference. That's it. It has nothing to do with category theory.

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steveklabnik8y ago

(Rust doesn't use Hindley-Milner, though the plan is to try to move closer to it in the future)

mrkgnaoOP8y ago

Oh, thanks for the correction.

It would appear that my knowledge is out of date: did Rust use something closer to H-M in the past? (Going off of https://github.com/rust-lang/rust/pull/15955 here.)

steveklabnik8y ago

For more, see here: https://www.reddit.com/r/rust/comments/6fs5q9/language_serve... see aturon's reply about that PR/blog post.

Rust has done almost everything in the past; I wouldn't be surprised if somewhere back in there it was actually HM. :)

jolux8y ago

Arguably optionals are monadic.

mrkgnaoOP8y ago

Optionals are also "applicative", but Haskellers used them for a long time before applicative functors became popular. A concept can support a certain way of thinking about it without everyone needing to think that way :)

jolux8y ago

you don't need to think that way, no, but i was pretty sure that rust optionals were modeled after the maybe monad. perhaps not.

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0 pointsmrkgnao8y ago0 comments

Rust uses Hindley-Milner type inference. OCaml uses Hindley-Milner. Swift apparently uses a variant of the system with more features.

None of these make use of monads or anything rooted in category theory.

https://en.wikipedia.org/wiki/Hindley%E2%80%93Milner_type_sy...

0 comments

steveklabnik8y ago

(Rust doesn't use Hindley-Milner, though the plan is to try to move closer to it in the future)

mrkgnaoOP8y ago

Oh, thanks for the correction.

It would appear that my knowledge is out of date: did Rust use something closer to H-M in the past? (Going off of https://github.com/rust-lang/rust/pull/15955 here.)

steveklabnik8y ago

For more, see here: https://www.reddit.com/r/rust/comments/6fs5q9/language_serve... see aturon's reply about that PR/blog post.

Rust has done almost everything in the past; I wouldn't be surprised if somewhere back in there it was actually HM. :)

jolux8y ago

Arguably optionals are monadic.

mrkgnaoOP8y ago

jolux8y ago

you don't need to think that way, no, but i was pretty sure that rust optionals were modeled after the maybe monad. perhaps not.

1 more reply

j / k navigate · click thread line to collapse