Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Algebraic Data Types for C99

github.com

Post reply on HN
Print view View original

11–20 of 233 posts

Re: Algebraic Data Types for C99

#11

Post by lupire »

tombert wrote: post #5

Interesting. Algebraic Data Types are almost always one of the things I miss when I use imperative languages. I have to do Java at work, and while I've kind of come around on Java and I don't think it's quite as bad as I have accused it of being, there's been several dozen instances of "man I wish Java had F#'s discriminated unions". Obviously I'm aware that you can spoof it with a variety of techniques, and often en…

Kotlin is JVM compatible and has ADTs.

Java has https://github.com/functionaljava/functionaljava

which is unsupported but stable.

Re: Algebraic Data Types for C99

#12

Post by odyssey7 »

jjice wrote: post #10
different_base wrote: post #3

One of the crimes of modern imperative programming languages is not having ADTs (except maybe Rust) built-in. It is such a basic mental model of how humans think and solve problems. But instead we got inheritance and enums which are practically very primitive.

I've never written Swift, but it seems like they have it too https://docs.swift.org/swift-book/documentation/the-swift-pr... I also would love a future where ADTs are more common in imperative languages

Swift “enumerations” are very nice.

Re: Algebraic Data Types for C99

#13

Post by lupire »

linkdd wrote: post #4

This is the work of a wizard. I've known C for almost 20 years, and never would I have thought the macro system was powerful enough to allow such black magic. This is awesome!

ADTs are mostly string replacement on generic structs and unions, plus tagging on the union. It's not a complicated use of macros.

Re: Algebraic Data Types for C99

#15

Post by zozbot234 »

different_base wrote: post #3

One of the crimes of modern imperative programming languages is not having ADTs (except maybe Rust) built-in. It is such a basic mental model of how humans think and solve problems. But instead we got inheritance and enums which are practically very primitive.

Pascal has had variant records since the 1970s.

Re: Algebraic Data Types for C99

#16

Post by tombert »

lupire wrote: post #11
tombert wrote: post #5

Interesting. Algebraic Data Types are almost always one of the things I miss when I use imperative languages. I have to do Java at work, and while I've kind of come around on Java and I don't think it's quite as bad as I have accused it of being, there's been several dozen instances of "man I wish Java had F#'s discriminated unions". Obviously I'm aware that you can spoof it with a variety of techniques, and often en…

Kotlin is JVM compatible and has ADTs. Java has https://github.com/functionaljava/functionaljava which is unsupported but stable.

Sure, and Scala has had ADTs since its inception as well I think, and that's also JVM. It's not ADTs, but Clojure does have some level of pattern matching/destructuring as well.

It wasn't that I though that the JVM was incapable of doing something like an ADT, just that vanilla Java didn't support it. While it's easy to say that "companies should just use Kotlin", that's a bit of a big ordeal if you already have a 15 year old codebase that's written in Java.

I've heard of but never used the Functional Java library, though it'd be a tough sell to get my work to let me import a library that hasn't been updated in two years.

Re: Algebraic Data Types for C99

#17

Post by adrian_b »

different_base wrote: post #3

One of the crimes of modern imperative programming languages is not having ADTs (except maybe Rust) built-in. It is such a basic mental model of how humans think and solve problems. But instead we got inheritance and enums which are practically very primitive.

Moreover, they have already been proposed by John McCarthy in October 1964, 60 years ago, for inclusion in the successor of ALGOL 60, which makes even more weird the lack of widespread support.

(And in fact Algol 68 had a better implementation than most later languages, but Algol 68 was missing completely any documentation suitable for newbies, like tutorials and programming examples, while not being promoted by any hardware vendor, like IBM or DEC, so it was doomed.)

Re: Algebraic Data Types for C99

#18

Post by estebank »

tombert wrote: post #5

Interesting. Algebraic Data Types are almost always one of the things I miss when I use imperative languages. I have to do Java at work, and while I've kind of come around on Java and I don't think it's quite as bad as I have accused it of being, there's been several dozen instances of "man I wish Java had F#'s discriminated unions". Obviously I'm aware that you can spoof it with a variety of techniques, and often en…

Everyone who hasn't used ADTs and pattern matching doesn't get what the big deal is all about. Everyone who is used to ADTs and pattern matching doesn't get what the big deal is all about, until they have to work in a language that doesn't have them. And everyone who just found out about them can't shut up about them being the best thing since sliced bread.

:)

Re: Algebraic Data Types for C99

#19

Post by debo_ »

different_base wrote: post #3

One of the crimes of modern imperative programming languages is not having ADTs (except maybe Rust) built-in. It is such a basic mental model of how humans think and solve problems. But instead we got inheritance and enums which are practically very primitive.

ADT feels like an unfortunately acronym-collision with "Abstract data types."

Re: Algebraic Data Types for C99

#20

Post by kaashif »

tombert wrote: post #9
different_base wrote: post #3

One of the crimes of modern imperative programming languages is not having ADTs (except maybe Rust) built-in. It is such a basic mental model of how humans think and solve problems. But instead we got inheritance and enums which are practically very primitive.

Yeah, when I first learned Haskell a million years ago, and Erlang slightly less than a million years ago, the pattern matching was so plainly obviously the "correct" way to do things; it just felt like it was exactly how I thought about problems, and all the constructs with if/switch/enums had been an attempt to force my brain thinking into something that executes. It honestly does annoy me that a lot of mainstream…

> when Java 8 added a lot of (well-needed) new syntax, it felt like that was an ideal opportunity to add ADTs and pattern matching

Well at least Java does now (as of Java 21) have pattern matching (including nested record destructuring) and sealed classes, which let you have decent sum types.

The one issue is that everything is nullable, but that's a wider Java issue.

Post reply on HN