5 ms·

Still, we want more things to be boldly and shamelessly borrowed from ML and Haskell * Universal pattern-matching (everywhere) * Obvious syntactic sugar fo

Still, we want more things to be boldly and shamelessly borrowed from ML and Haskell * Universal pattern-matching (everywhere) * Obvious syntactic sugar for defining and applying curried functions, partial application. * Type-classes (as a one single major innovation in PL since Smalltalk) * receive (or select) with pattern matching (Erlang, protobuf). * first class typed channels (Go). * multimethods (CLOS). Thank you!

foota 8y ago
What do protobufs have to do with select?
- throwaway487550 8y ago
  Protobuf does implicitly, via code-generation, what could be done explicitly via defining algebraic types and pattern-marching on receive, a-la Erlang.
paavohtl 8y ago
> Universal pattern-matching Where are you missing pattern matching? The only place I can think of where it can't be used currently is the function signature. Might be hard to retrofit to the current syntax. > Type-classes Rust's traits are type-classes. > first class typed channels Why do they need to be first class? Unlike Go, Rust's type system is powerful enough that type-safe channels can be (and have been) implemented as a library. See crossbeam-channel.
- steveklabnik 8y ago
  You can use pattern matches in function signatures.
  - throwaway487550 8y ago
    How could I write this in Rust? fun map f [] = [] | map f (x::xs) = (f x) :: map f xs; And boy, no TCO. What a shame.
    - steveklabnik 8y ago
      You can only use irrefutable patterns. You’d write this by writing a match in the body. There’s been talk of maybe supporting this directy but it’s so niche there’s not a ton of demand. There is TCO, just not guaranteed. We’d like it; we have even reserved a keyword. Needs an RFC though.
- throwaway487550 8y ago
  > Rust's traits are type-classes. And the functor typeclass in Rust looks like...?
  - paavohtl 8y ago
    Rust doesn't currently have higher-kinded types, which are a separate feature from typeclasses. Implementing a true Functor trait is impossible without HKT, though the lack of it and other FP abstractions generally speaking hasn't been an issue.

foota 8y ago

What do protobufs have to do with select?

throwaway487550 8y ago
Protobuf does implicitly, via code-generation, what could be done explicitly via defining algebraic types and pattern-marching on receive, a-la Erlang.

paavohtl 8y ago

> Universal pattern-matching Where are you missing pattern matching? The only place I can think of where it can't be used currently is the function signature. Might be hard to retrofit to the current syntax. > Type-classes Rust's traits are type-classes. > first class typed channels Why do they need to be first class? Unlike Go, Rust's type system is powerful enough that type-safe channels can be (and have been) implemented as a library. See crossbeam-channel.

steveklabnik 8y ago
You can use pattern matches in function signatures.
- throwaway487550 8y ago
  How could I write this in Rust? fun map f [] = [] | map f (x::xs) = (f x) :: map f xs; And boy, no TCO. What a shame.
  - steveklabnik 8y ago
    You can only use irrefutable patterns. You’d write this by writing a match in the body. There’s been talk of maybe supporting this directy but it’s so niche there’s not a ton of demand. There is TCO, just not guaranteed. We’d like it; we have even reserved a keyword. Needs an RFC though.
throwaway487550 8y ago
> Rust's traits are type-classes. And the functor typeclass in Rust looks like...?
- paavohtl 8y ago
  Rust doesn't currently have higher-kinded types, which are a separate feature from typeclasses. Implementing a true Functor trait is impossible without HKT, though the lack of it and other FP abstractions generally speaking hasn't been an issue.