Kotlin/KEEP on Hacker News

Kotlin itself has opted for inline union types to represent error results: https://github.com/Kotlin/KEEP/blob/main/proposals/KEEP-0441... The existing Result type was a mistake to expose to users, IMO, as it encourages…

comment by tadfisher · 2026-04-13 · in A perfectable programming language

…which seems to be the same as this proposal. From the GitHub discussion, I see this comment ( https://github.com/Kotlin/KEEP/discussions/447#discussioncom... ): > The difference between checked exceptions from java and error unions in this…

comment by armchairhacker · 2026-01-23 · in Kotlin's rich errors: Native, typed errors without exceptions

…From the proposal discussion[0], the runtime representation on the JVM will just be `Object`. [0]: https://github.com/Kotlin/KEEP/discussions/447#discussioncom...

comment by pianoben · 2026-01-23 · in Kotlin's rich errors: Native, typed errors without exceptions

…I think it's pretty good and prevents a lot of boiler plate associated with results/exceptions: https://github.com/Kotlin/KEEP/blob/main/proposals/KEEP-0441... . They propose a similar construct to try! with !! like they have for nullable…

comment by vips7L · 2025-12-06 · in Thoughts on Go vs. Rust vs. Zig

…puts Kotlin away from Java making interop a lot harder. [0] https://openjdk.org/jeps/8323658 [1] https://github.com/Kotlin/KEEP/blob/main/proposals/KEEP-0441...

comment by vips7L · 2025-11-11 · in Error ABI

…errors that the OpenJdk team will invest in making checked exceptions better, but only time will tell. [0] github.com/Kotlin/KEEP/blob/main/proposals/KEEP-0441-rich-errors-motivation.md [1] https://openjdk.org/jeps/8323658

comment by vips7L · 2025-09-05 · in Type-safe and user-friendly error handling in Swift 6

…You can find a pretty good overview of the Kotlin error handling phylosphy here [1] [1] https://github.com/Kotlin/KEEP/blob/master/proposals/stdlib/...

comment by dtech · 2024-05-22 · in What's New in Kotlin 2.0.0

`Either<MyError, Foo> foo()` and `Foo foo() throws MyError` and are pretty much isomorphic. https://github.com/Kotlin/KEEP/blob/master/proposals/stdlib/...

comment by ackfoobar · 2024-04-19 · in JEP draft: Exception handling in switch

…a nearly identical feature at the language level, which will be optimizable when Valhalla ships: https://github.com/Kotlin/KEEP/blob/master/notes/value-class... > In the future, in a Valhalla-capable JVM, JVM primitive classes will enable…

comment by brundolf · 2023-12-03 · in Project Valhalla: A look inside Java's epic refactor

…be reasonably handled by the caller and encapsulate failures in the return type if they can. [1] https://github.com/Kotlin/KEEP/blob/master/proposals/stdlib/...

comment by dtech · 2023-07-13 · in Unchecked Java: Say goodbye to checked exceptions

Lenses work today. And I think the value class feature will be awesome. https://github.com/Kotlin/KEEP/blob/master/notes/value-class...

comment by ackfoobar · 2023-01-17 · in Making Lenses Practical in Java

Kotlin has value classes. Here's a good overview of how they work in Kotlin: https://github.com/Kotlin/KEEP/blob/master/notes/value-class... That document is a few years old now and was intended as a design document. But Value classes…

comment by jillesvangurp · 2022-05-20 · in Rust: A Critical Retrospective

I'd be very interested in a comparison between scala 3 using/given and Kotlin new context receivers https://github.com/Kotlin/KEEP/blob/master/proposals/context...

comment by SemanticStrengh · 2022-05-14 · in Java record pattern matching in JDK 19

…I'm not convinced by their usefulness, the feature will be available in Kotlin in a few months: https://github.com/Kotlin/KEEP/issues/259 I'd even argue it is more useful in Kotlin since the language is state of the art regarding it's…

comment by The_rationalist · 2021-12-26 · in State of Valhalla

Yes and no: https://github.com/Kotlin/KEEP/blob/master/notes/value-class... "value class" is the next step for inline classes. They are going to behave very much like Swift's struct and its "mutating methods". And they are going to be…

comment by ragnese · 2021-04-01 · in A categorized list of all Java and JVM features since JDK 8 to 16

…logic programming related futures on current mainstream multi paradigm languages like in kotlin https://github.com/Kotlin/KEEP/pull/199

comment by The_rationalist · 2020-09-27 · in Picat 3.0 released (logic-based multi-paradigm programming language)

…and it should come in a following release, especially since Java is getting pattern matching. https://github.com/Kotlin/KEEP/pull/213 But if your point was that macros allows to modify the abstract syntax tree, Kotlin compiler plugin API…

comment by The_rationalist · 2020-05-28 · in Pros and Cons of Nim

…? There was a (unlikely to be merged at least in its current form) proposal for Kotlin -> https://github.com/Kotlin/KEEP/pull/199/files Maybe LINQ from .NET could be included There is also chalk from Rust https://github.com/rust-lang/chalk

comment by The_rationalist · 2020-05-19 · in Ask HN: Production Prolog in 2020?

…There's a proposal brought forward by the Arrow people that has attracted a lot of attention. https://github.com/Kotlin/KEEP/pull/87 If if that does not succeed, the Arrow folks are working on a meta compiler (think template Haskell but…

comment by adimitrov · 2019-12-07 · in The Road to Valhalla

Typeclasses can be introduced; there's a PR doing that in a reasonable manner: https://github.com/Kotlin/KEEP/pull/87 It's not shot down. Instance derivation is likely not impossible when typeclasses support is there. I wonder how…

comment by nine_k · 2018-07-06 · in Rise of Kotlin: A Programming Language for the Next Generation

…is planned for Kotlin 1.1 [1], and it's primarily useful for sealed classes (I've wanted this). [1] https://github.com/Kotlin/KEEP/blob/master/proposals/data-cl...

comment by kilink · 2016-09-25 · in Kotlin in Production – What Works, Whats Broken