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Would anyone here assert that there's any particular programming language that's better for writing emulators, virtual machines, bytecode interpreters, etc? Wh
by derefr 1y ago
Would anyone here assert that there's any particular programming language that's better for writing emulators, virtual machines, bytecode interpreters, etc?
Where, when I say "better", I'm not so much talking about getting results that are particularly efficient/performant; nor in making fewer implementation errors... but more in terms of the experience of implementing an emulator in this particular language, being more rewarding, intuitive, and/or teaching you more about both emulators and the language.
I ask because I know that this sort of language exists in other domains. Erlang, for example, is particularly rewarding to implement a "soft-realtime nine-nines-of-uptime distributed system" in. The language, its execution semantics, its runtime, and its core libraries, were all co-designed to address this particular problem domain. Using Erlang "for what it's for" can thus teach you a lot about distributed systems (due to the language/runtime/etc guiding your hand toward its own idiomatic answers to distributed-systems problems — which usually are "best practice" solutions in theory as well); and can lead you to a much-deeper understanding of Erlang (exploring all its corners, discovering all the places where the language designers considered the problems you'd be having and set you up for success) than you'd get by trying to use it to solve problems in some other domain.
Is there a language like that... but where the "problem domain" that the language's designers were targeting, was "describing machines in code"?
- chickenzzzzu 1y agoC89
- johnnyjeans 1y agosml, specifically the MLTon dialect. It's good for all the same reasons ocaml is good, it's just a much better version of the ML-language in my opinion. I think the only thing that ocaml has that I miss in sml is applicative functors, but in the end that just translates to slightly different module styles.
- wk_end 1y agoCan you expand on what makes SML better, in your eyes, than OCaml? IMO: it's certainly "simpler" and "cleaner" (although it's been a while but IIRC the treatment of things like equality and arithmetic is hacky in its own way), which I think causes some people to prefer SML over aesthetics, but TBH I feel like many of OCaml's features missing in SML are quite useful. You mentioned applicative functors, but there's also things like labelled arguments, polymorphic variants, GADTs, even the much-maligned object system that have their place. Is there anything SML really brings to the table besides the omission of features like this?
- johnnyjeans 1y ago> the treatment of things like equality and arithmetic is hacky in its own way mlton allows you to use a keyword to get the same facility for function overloading that is used for addition and equality. it's disabled by default for hygienic reasons, function overloading shouldn't be abused. https://baturin.org/code/mlton-overload/ https://baturin.org/code/mlton-overload/ > labelled arguments generally speaking if my functions are large enough for this to matter, i'd rather be passing around refs to structures so refactoring is easier. > polymorphic variants haven't really missed them. > GADTs afaik being able to store functors inside of modules would fix this (and I think sml/nj supports this), but SML's type system is more than capable of expressing virtual machines in a comfortable way with normal ADTs. if i wanted to get that cute with the type system, i'd probably go the whole country mile and reach for idris. > even the much-maligned object system that have their place never used it. > Is there anything SML really brings to the table besides the omission of features like this? mlton is whole-program optimizing (and very good at it)[1], has a much better FFI[2][3], is much less opinionated as a language, and the parallelism is about 30 years ahead[4]. the most important feature to me is that sml is more comfortable to use over ocaml. being nicer syntactically matters, and that increases in proportion with the amount of code you have to read and write. you dont go hiking in flip flops. as a knock-on effect, that simplicitly in sml ends up with a language that allows for a lot more mechanical sympathy. all of these things combine for me, as an engineer, to what's fundamentally a more pragmatic language. the french have peculiar taste in programming languages, marseille prolog is also kind of weird. ocaml feels quirky in the same way as a french car, and i don't necessarily want that from a tool. [1] - http://www.mlton.org/Performance http://www.mlton.org/Performance [2] - http://www.mlton.org/ForeignFunctionInterface http://www.mlton.org/ForeignFunctionInterface [3] - http://www.mlton.org/MLNLFFIGen http://www.mlton.org/MLNLFFIGen [4] - https://sss.cs.purdue.edu/projects/multiMLton/mML/Documentation.html https://sss.cs.purdue.edu/projects/multiMLton/mML/Documentat...
- vkazanov 1y agoI love, love, love StandardML. I respect the sheer power of what mlton does. The language itself is clean, easy to understand, reads better than anything else out there, and is also well-formalised. I read (enjoyed!) the tiger book before I knew anything about SML. Sadly, this purism (not as in Haskell but as a vision) is what probably killed it. MLTon or not, the language needed to evolve, expand, rework the stdlib, etc. But authors were just not interested in the boring part of language maintenance.
- makeset 1y agoI remember working through Appel's compiler textbook in school, in SML and Java editions side by side, and the SML version was of course laughably more concise. It felt like cheating, because it practically was.
- pjmlp 1y agoNowadays you could make the Java version quite similar to the SML one, if there would be a new edition. I have been looking forward to ML like capabilities on mainstream since using Caml Light. Regarding those books, while we used the Java version, alongside JavaCC, when time came to actually buy the book, I also got the SML edition.
- vkazanov 1y agoHeh... I got the C version first, which was a mess, only to immediately order the ML one. > have been looking forward to ML like capabilities on mainstream since using Caml Light. Modern Java is not built around ADTs and pattern matching, these things feel a bit bolted on. SML feels almost like a compiler writing DSL.
- pjmlp 1y agoThe difference is that I get to use Java at work, and never will be able to use SML, perfection usually fails in mainstream adoption, as proven by the whole worse is better mindset languages. I rather have Java, C#, C++, Kotlin, Rust,.... with their imperfections to ML, Smalltalk, and Lisp ideas, than hoping for getting the right languages at the workplace. Fully agree on the C edition.
- vkazanov 1y agoTrue. Good enough wins. Worse is better rules. Release early... and so on. I am old enough to remember the full drama behind adding lambda to python, and resistance to bits of functional goodies coming from lisps. But here we are. Java is an aaaalmost acceptable language! While scheme, standardml and numerous other perfect little languages are mostly just Wikipedia pages now.
- corysama 1y agoWell, there’s always https://pypi.org/project/rpython/ https://pypi.org/project/rpython/
- foobiekr 1y agoC is probably the best language for this.
- filleduchaos 1y agoI quite frankly disagree. From personal experience I don't think there's any mainstream programming language that in itself teaches you anything much about emulating systems like the Game Boy or NES - in fact, I'd go so far as to say that none of them even at least yield elegant and accurate implementations. People write "production-grade" emulators in C because it's fast, not because it's uniquely suited to the domain as a language.
- IshKebab 1y agoC isn't really the best language for anything anymore. Maybe as a compilation target for other languages.
- pjmlp 1y agoOnly from a UNIX culture mindset.
- MangoToupe 1y agoAs opposed to what?
- pjmlp 1y agoEveryone else that understands C is not the first systems language to ever exist since FORTRAN in 1958, nor it will be around forever outside anything tied to UNIX/POSIX.
- MangoToupe 1y agoC isn't even a systems language lol, it's too delicate to rely on for systems.
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- wk_end 1y agoVerilog? ...just kidding (maybe). Assuming we're talking about a pure interpreter, pretty much anything that makes it straightforward to work with bytes and/or arrays is going to work fine. I probably wouldn't recommend Haskell, just because most operations are going to involve imperatively mutating the state of the machine, so pure FP won't win you much. The basic process of interpretation is just: "read an opcode, then dispatch on it". You'll probably have some memory address space to maintain. And that's kind of it? Most languages can do that fine. So your preference should be based on just about everything else: how comfortable are you using it, how much do you like its abilities to interface with your host platform, how much do you like type checking, and so on.
- deleted 1y ago[deleted]
- grg0 1y agoHaskell excels at DSLs and the sort of data manipulation needed in compilers. OCaml, Lisp, and really any language with support for ADTs and such things do the trick as well. You can even try hard with modern C++ and variant types and such, but it won't be as pretty. Of course, if you actually want to run games on the emulator, C or C++ is where the game is. I suppose Rust would work too, but I can't speak much for its low-level memory manipulation.
- wk_end 1y agoHaskell and OCaml are excellent for compilers, because - as you suggest - you end up building, walking, and transforming tree data structures where sum types are really useful. Lisp is an odd suggestion there, as it doesn’t really have any built-in support for this sort of thing. At any rate, that’s not really the case when building an emulator or bytecode interpreter. And Haskell ends up being mostly a liability here, because most work is just going to be imperatively modifying your virtual machine’s state.
- materielle 1y agoI’d also point out, that even in the compiler space, there are basically no production compilers written in Haskell and OCaml. I believe those two languages themselves self-host. So not saying it’s impossible. And I have no clue about the technical merits. But if you look around programming forums, there’s this ideas that”Ocaml is one of the leading languages for compiler writers”, which seems to be a completely made up statistic.
- pjmlp 1y agoWe must be looking at different compilers.
- runevault 1y agoI don't know that many production compilers are in them, but how much of that is compilers tending towards self hosting once they get far enough along these days? My understanding is early Rust compilers were written in Ocaml, but they transitioned to Rust to self-host.
- alaaalawi 1y agoone of the options for fast iterations would be Forth. in its circles, it famous for generation targets and cross compiling between archs. seaech the net you shold find plenty.
- UncleOxidant 1y agoOCaml doesn't seem like a bad choice here. Haven't played with it much, but I wonder if Racket might be a good choice as well?
- alaaalawi 1y agoAlso another option for fun in the browser Elm. check out similar older project https://github.com/Malax/elmboy https://github.com/Malax/elmboy
- MangoToupe 1y agoI want to dissuade anyone possible from looking at Elm. I used it professionally for about six months before I convinced my org to switch away. It simply doesn't have the type system to support complex programs, and the maintainers have a really noxious relationship with the community.
- alaaalawi 1y agochill bro. spending some time on Elm is not the end of the world and not a serious issue! the question was about learning and not concerned about production and this was one of the available examples to maybe have a look at.
- MangoToupe 1y agoWeirdly hostile way to treat someone contributing to the conversation.
- phplovesong 1y agoOcaml is really good for this, and is usually "fast enough" for most things. When you REALLY need speed, there is the oxcaml project by jane street that gets you all sorts of perf improvements and close to C speed, while still having a GC for things not critical for raw speed.
- MangoToupe 1y ago> Would anyone here assert that there's any particular programming language that's better for writing emulators, virtual machines, bytecode interpreters, etc? No, absolutely not. Emulation is super easy to implement in any language with arrays (constant-time lookup of arbitrary indices) and bit operations. At least before considering JIT. And even functional languages have arrays and bitwise operations.
- deaddodo 1y agoI would argue that systems languages (C, C++, Rust, and Zig standout) are the most “fulfilling” (in my experience). The reason being that the methodologies are far more orthogonal. A uint8 directly represents a byte in memory, doing a memcpy is equivalent to a blit, etc. You spend far less time trying to wrangle a JavaScript Number type into acting like a byte/word/etc for a bitshift operation for a simple ADC. A very simple example that you’ll run into in the first day of writing a js emulator. That all being said, if the language can paint to some surface and has the memory size to handle the machine you’re emulating, they’re all roughly equivalent. So the answer becomes “whichever language you’re most comfortable with is the one writing an emulator in is most enjoyable”.