[chrismorgan]

It only looks messy. It’s not particularly difficult to read, and with what it’s expressing there’s really no way of expressing it in shorter terms. “A method on an Option[T] named Map, generic over type U, taking one argument, a function from a T to a U, and returning an Option[U].”

Mind you, I wouldn’t mind colons and arrows as separators which I think make it easier to read; here’s what it’d look like in a somewhat more Rust-like syntax:

  fn Map<U: any>(self: Option<T>, f: fn(a: T) -> U) -> Option<U> { ... }

I would also note that signatures like these are mostly found in foundational types; they take a bit more effort and practice to write, but you don’t often have to do so; and have the outcome that the API is more pleasant to use—no more interface objects and downcasting everywhere, in Go terms.

[SergeAx]

I got your point, and it's worth mentioning that there's that rare moment when Rust looks more readable than Go.

Concerning resulting API: isn't code generation solves a problem with interface objects and downcasting?

[chrismorgan]

I’m not sure what you’re asking. Generics are code generation (look into the term monomorphisation), just automatic and managed by the compiler for better convenience than manual code generation by other means, and type safe for better correctness and efficiency than interface objects and downcasting.

[newusertoday]

Thank you, i wasn't able to decipher the syntax until i read your comment “A method on an Option[T] named Map, generic over type U, taking one argument, a function from a T to a U, and returning an Option[U].”