6 ms·
Four Lectures on Standard ML (1989) [pdf]
- toolslive 2y agoStudying SML should be part of the entry examination for programming language designers. It's old, has its warts, but is still vastly superior to most things that came later. (Type inference? check! Pattern matching? check! TCO? check!. Performance ? excellent!, ...)
- ngruhn 2y agoit's crazy, it took "the industry" 30+ years to adopt this stuff
- fire_lake 2y agoAnd they still haven’t! Although expressions over statements would be a breaking change - I can’t see any mainstream language making this switch.
- tialaramex 2y agoBarry Revzin has written a paper to try to give C++ expressions like this. It's ugly, even by the standards of C++ but it would work. The rationale is that C++ 29 or C++ 32 wil probably get pattern matching and pattern matching doesn't have great ergonomics if everything is a statement rather than an expression. There are plenty of other things C++ will need to fix once it gets pattern matching, but the direction makes sense if you insist on trying to teach this particular old dog new tricks. Also, I think Rust would consider itself to be a mainstream language, though they aren't techically "making this switch" because the language has always been expresion oriented from the outset. The Book has about two paragraphs about the statements in the language and then a whole chapter on expressions because almost everything is an expression.
- tmountain 2y agoStill waiting on real pattern matching in TyoeScript.
- no_wizard 2y agoYou won’t get it till TC39 adopts it
- BalinKing 2y agoI actually think it's becoming fairly common these days—IIRC Ruby and Rust both prioritize expressions over statements.
- int_19h 2y agoThey do, but the fact that there is even a distinction at this point is rather baffling. If your type system has the unit type and the bottom type, all statements should just be expressions having one of those two types.
- fire_lake 2y agoPeople really like their early return statements however.
- needlesslygrim 2y agoWell, Rust barely has statements [1]. Nearly everything in Rust is an expression, and AFAIK statements /are/ essentially expressions that yield `()` [2]. [1]: https://doc.rust-lang.org/reference/statements.html https://doc.rust-lang.org/reference/statements.html [2]: https://play.rust-lang.org/?version=stable&mode=debug&edition=2024&gist=12aacef98d63cb28ec12b0ae96308619 https://play.rust-lang.org/?version=stable&mode=debug&editio...
- steveklabnik 2y ago> AFAIK statements /are/ essentially expressions that yield `()` This isn't true. The inverse is true, "expression statements" can turn an expression into a statement. What you're seeing in the playground is just how blocks are defined[1]: > The syntax for a block is {, then any inner attributes, then any number of statements, then an optional expression, called the final operand, and finally a }. In this case, you have one statement, and no optional expression. And so: > The type of a block is the type of the final operand, or () if the final operand is omitted. So that's how this works. Now, that being said, I don't think it's too terrible of a mental model to think of this situation in that way. But if we're getting into nitty-gritty details, that's not actually how it works. 1. https://doc.rust-lang.org/stable/reference/expressions/block-expr.html https://doc.rust-lang.org/stable/reference/expressions/block...
- Almondsetat 2y agodo you have any research that points to these things being useful for the industry?
- sudahtigabulan 2y agoThe languages that were actually adopted by the industry are not exactly full of great useful stuff: https://www.destroyallsoftware.com/talks/wat https://www.destroyallsoftware.com/talks/wat
- cmrdporcupine 2y agoHaving SML (or at least OCaml) as a known language definitely would help engineers when they get into the industry and start using Rust. Back in the day when I played with these things I preferred SML/NJ over OCaml, but OCaml "won" the battle for headspace. I'd consider using OCaml for new projects, I really like the language family.
- xyproto 2y agoI also prefer SML over OCaml. I wonder how F# feels and want to give it a shot.
- int_19h 2y agoF# doesn't have many of OCaml's more advanced features. In particular, no functors and no polymorphic variants. Also the OO system is basically .NET, which isn't that surprising (but means that you don't get the neat row typing with inference that OCaml does). OTOH some of the choices it makes are a bit more pragmatic - e.g. arithmetic is overloaded for ints and floats, locals can be marked as mutable similar to record fields, and fields are scoped to record types (so different types can use the same field name).
- sheepscreek 2y agoIt’s incredible how much of an understatement it is to say that F# and OCaml were “inspired” by Standard ML. They’re practically step-siblings, sharing more similarities than I could have ever imagined. Edit: Obviously, F# is the step-sibling here, given its half-dotnet parentage. However, they’re all solid choices. Their spectacular type inference makes coding in them a very gratifying experience. I can only think of TypeScript as the closest to them among the more popular modern languages.
- moomin 2y agoC#’s inference is pretty good these days. As with most things with powerful type inference, you can make a real mess if you put your mind to it.
- int_19h 2y agoFor those curious about the differences between Standard ML and OCaml. http://adam.chlipala.net/mlcomp/ http://adam.chlipala.net/mlcomp/
- rokkamokka 2y agoThis was the language they taught in our functional programming course while I was doing my CS degree. That was around 15 years ago now. I wonder if they still use it in the course
- deleted 2y ago[deleted]
- nextos 2y agoThe Little Series, famous for The Little Schemer book, published The Little MLer in 1998. It's probably their lesser known volume, but IMHO it makes a terrific job at teaching the ML family and its features.
- cantrevealname 2y agoFYI for everyone: This is not about Machine Learning. It is about a programming language called Standard ML where ML stands for Meta Language[1]. [1] https://en.wikipedia.org/wiki/Standard_ML https://en.wikipedia.org/wiki/Standard_ML
- tialaramex 2y agoI was taught the Standard ML of New Jersey (which as a non-American I did not realise is a joke, it's referring to the company now known to you as Exxon, the Standard Oil of New Jersey) at university. I strongly believe that - although my home institution no longer teaches an ML as first language - this is the best way to teach CS to undergraduates. An ML has all the fundamental ideas you will need to also teach about this discipline, and (so long as you choose e.g. SML/NJ or similar, not Rust or something) it won't be a language the average teenager you recruited might already know, so the week 1 exercise showing they've understood what they're doing is actually work for all of your students, averting a scenario where some of them drift away only to realise at exam time that they haven't learned a thing.
- sshine 2y agoThank you for sharing this American joke. Standard ML was my go-to language for many years. I always found SML/NJ complicated both to compile and use, compared to... ...well, pretty much every other compiler: Moscow ML, Poly/ML, MLton, MLKit.
- jjice 2y agoAgreed - we wrote an ML style language in my uni compilers course and it was taught by the primary maintainer of MLTon (Dr Fluet is a great guy). Since it’s full program optimizing, the compilation took a while. He told us to give SML NJ a try for faster compilation but slower execution. It was a headache and only marginally faster compilation for our use case. That said, it’s the OG so I give it some slack. I did enjoy MLton though, but it’s easier to do when the instructor wrote it.
- smlismyhomeboy 2y ago
- uzername 2y agoWe used SML in my undergrad compilers course. I really loved the language and I started exploring other languages outside of class after that.
- swatson741 2y agoDefiantly worth studying SML imo. Pattern matching is a cool feature. Although it's not as comprehensive as most of the pattern matchers in Lisp. You can't match on bitfields, comparisons other than equality by value, etc. Datatypes are just ok. Classes would be better. It's sort of strange to represent lists (and everything else) as enumerations. It's not really essential or fundamental but I guess that's what Lisp is for.
- ossopite 2y agoI suppose by enumerations you mean sum types. I would argue that these are pretty fundamental? you have product types (structs/records/tuples) - a value is made up of x and y - and sum types - a value can be either X or Y. I think the combination of these is what you need to precisely express any concrete data type.
- swatson741 2y agoI did mean sum types, variants, etc. It's not really clear what I meant by representing the data but I'm referring to type inference. SML can't solve the problem, and Lisp doesn't have it.
- msarnoff 2y agoMy favorite bit of SML trivia: the infix function composition operator is “o” — lowercase letter o — so you can write ‘(f o g)(x)’ just like mathematical notation.
- trollied 2y agoMy CS degree course used SML as the first language to teach everyone in the first semester. Put everyone on the same level, as it was unlikely people would have prior experience. Also made it easy to teach things like recursion. Really enjoyed it.
- peterstjohn 2y agoHa, same here! It really helped my imposter syndrome, as I overheard a couple of guys talking about the ARM assembly they were doing on their Archimedes on the first day…and I hadn't written anything fancier than QuickBASIC at the time…
- trollied 2y agoWas actually lucky enough to be taught by the co-inventor of the ARM cpu. Furber is awesome.
- peterstjohn 2y agoFor my sins, I didn't actually realise how great that was until quite a bit afterwards! ;)
- ckmate-king-2 2y agoNote that these lectures are from 1989, but the definition of Standard ML was revised in 1997. See, e.g., https://www.smlnj.org/sml97.html https://www.smlnj.org/sml97.html.