The Flix Programming Language
flix.dev
flix.dev
- We are trying to make the entire compiler resilient (error-tolerant), incremental, and parallel. We have managed to make every single compiler phase (of which there are 28) parallel. This has already led to significant speed-ups. We are now trying to increase the degree of parallelism within each phase. We are also working on error resilience to provide LSP support no matter what errors a program contains (syntax, naming, type). For example, it should be possible to rename a variable even if the program currently has multiple errors.
- We are adding support for algebraic effects and handlers. This will allow users to define and handle their own effects.
- We are also exploring a novel way to combine type classes ("traits") and effects.
- We have recently added support for package management and integration with Maven.
In summary, we are already in a great spot, and useful programs can be written in Flix today. I encourage you to check out the documentation: https://doc.flix.dev/ and to try Flix!
(I am one of the developers of Flix).
Looks incredibly cool though.
Are there any [plans for] supply chain attack mitigations?
Naively searching, I find https://github.com/flix/flix/issues/4380#issuecomment-123641... (Proposed Principle: A package can be declared as "safe") and https://github.com/flix/flix/issues/2837 (Add capability-safety to polymorphic effects?) the latter closed with working on something related to this https://github.com/flix/flix/issues/3000 (The Road to Algebraic Effects).
Plea to all language/languge ecosystem designers in 2023+ to design ahead for supply chain attack mitigations. Austral is one new language that appears to be doing so https://borretti.me/article/how-capabilities-work-austral ... Kudos to those retrofitting to existing ecosystems. I guess Flix is somewhere in the middle, not new (2015?) but still being designed/not huge legacy constraints. Anyway, thanks!
> Flix supports region-based local mutation, which makes it possible to implement pure functions that internally uses mutable state and destructive operations, as long as these operations are confined to the region.
> We can use local mutation when it is more natural to write a function using mutable data and in a familiar imperative-style while still remaining pure to the outside world.
> We can also use local mutation when it is more efficient to use mutable data structures, e.g. when implementing a sorting algorithm.
Another language with a feature like this is F* (or FStar), but I think it uses a different kind of compile-time analysis.
Haskell actually kind of lets you do it through the ST monad (there's a function called runST that turns mutable code inside the ST monad into pure code). But F* (and Flix) can do it implicitly
An Erlang/Elixir process is single-threaded by definition, so there is no contention and in-place mutation could be allowed.
Flix – Safe, reliable, concise, and functional-first programming language - https://news.ycombinator.com/item?id=31448889 - May 2022 (42 comments)
Flix – Next-generation reliable, concise, functional-first programming language - https://news.ycombinator.com/item?id=25513397 - Dec 2020 (84 comments)
The Flix Programming Language - https://news.ycombinator.com/item?id=19928153 - May 2019 (2 comments)
Also this part made me let out an audible "wow":
> We can exploit purity reflection to selectively use lazy or parallel evaluation inside a library without changing the semantics from the point-of-view of the clients.
Will definitely keep an eye on this language! The syntax seems a little odd (inferring type parameters for functions?) but I'm sure I could get used to it.
> Dividing by zero yields zero. https://www.hillelwayne.com/post/divide-by-zero/
That's one interesting point I would love to read any opinions on.
Edit: Here's a HN discussion about the `divide by zero` article - https://news.ycombinator.com/item?id=17736046
[0] https://tutorial.ponylang.io/gotchas/divide-by-zero.html
In the year since I wrote this post, Pony added partial division. I still don’t know anything about the language but they’ve been getting grief over this post so I wanted to clear that up.
https://tutorial.ponylang.io/expressions/arithmetic.html#par...
I think Hillel's post was just saying that 1/0 == 0 doesn't lead to any mathematical contradictions.
Another way to think about it is that I believe 1/0 == 42 and 1/0 == 43 are just as valid. They don't lead to contradictions.
[In ZF set theory] Since 0 is not in the domain of recip, we know nothing about the value of 1 / 0; it might equal √2, it might equal R, or it might equal anything else.
But I don't think you want to use a language where 1/0 == 42, and likewise for 0.
public double magnitude
{
get
{
double c = max_magnitude;
return c > 0 ? Math.Max(c, c * (this / c)._internal_magnitude) : 0;
}
}
Example see: https://github.com/Release-Candidate/flix-test
* Example at the top
* Link to playground
* Explanation of all the features, with examples!
* Says which features are unique
The only thing I was found wondering was "why datalog"?
Language looks pretty good.
I always say that purely in terms of design my ideal language is high-level Haskell, low-level C. Conceptually, purely functional design is how programming "should" (note the quotes) be, but doing so down to the level of functions is both not very practical (some algorithms are just easier to express in terms pointers moving around rather than folds, reduces and the like), and makes it hard to reason about performance (especially memory, and most especially if you throw laziness in the mix).
But then again, I write my own stuff in python because I'm a lazy fuck, so probably it's not meant to be :(
That's similar to what I used to say. I was devastated to see the BitC project implode, but then Rust appeared and took up the mantle. It's not perfect by any means but it's influential enough to drag the whole field of PL development kicking and screaming in that general direction.
In spite of all the retarded monkeys in its fanbase, I always thought it was an interesting project. Popular languages today are much more similar than they used to be, they are basically "converging", Rust's willingness to try something new must be applauded.
Still many pain points, still a bit of a "puzzle language", too much of a scatterbrain approach in the governance and design direction, but even if it had no other influence than to force people to think about the problems of low-level programming, that would be still a massive plus in my book.
The reason why Haskell and other popular FP languages all require a GC.
But functional programming is fully supported and lack of GC is not an issue, since you can use Rc<> and Arc<> where needed. (Support for 'pluggable' tracing Gc<> will probably be added at some point, but it will need local allocators, which are not a stable feature yet.)
Why / why not?
The other major neat thing about functional languages is how they let you treat functions like objects, but most modern programming languages have adopted that as well, so it's not a big differentiator anymore.
It's definitely a different way of thinking and it has a lot of benefits. However, some of the downsides (which Flix seems to fix with region-based local mutation) might be implementing a sort that keeps two copies of a list in memory just to return the second list and discard the first. Depending on your list, this may not be an issue.
In theory, writing in a functional language that allows only "pure" functions (aka. functions w.o. side effects), makes it easier to control state.
In practice, side effects exists and are required for programs to do anything useful.
In my opinion, one mistake of many purely functional languages was to be so focused on this purity, that it made it needlessly hard to write useful code in them, especially for people coming from an imperative/procedural/oop style of doing things. And you need these people if you want your method to gain traction, because the vast majority of code written, is imperative.
The irony is, that FP could probably have had a lot more success if it didn't clamour on about pure functions so much, and was less focused on implementations (aka. languages) than on methodology (aka. coding style) Because it is perfectly possible to write pure functions in most languages, including OOP language, even if those functions are not "pure" internally, or are not "pure" all the time and under all circumstances.
And yes, doing so has really nice advantages. I have refactored quite alot of codebases into using a more functional approach, and what I found was that this makes it harder to introduce bugs, makes it easier to track bugs, and makes it easier to reason about my code.
So yeah, functional programming, used if and where it makes sense, does work, and is useful.
Except functional languages like Lisps and the MLs never were pure, the only (used by a significant number of people) has been Miranda/Haskell (ignoring Coq and the other proof assistents). Or, to put it in other words: ML (no, not that ML) turned 50 this year, Scheme is oder than 50 too and Miranda/Haskell ~36. There never had been a shortage of "impure" functional languages since OOP existed.
So maybe it's time for FP as a whole to accept the fact, that there seems to be something fundamental about the way it's paraded implementations look and feel like, that puts off a lot of programmers.
Maybe it's time for FP to accept that the paradigm as a whole has a lot to contribute that is useful to everyone, but doesn't need a new language with largely different syntactic constructs to do so.
Many languages are in use for different things without the need for a language to win. It is a bit anthropomorphic to approach tools like that IMO.
Instead, there has been a healthy influence of more research FP languages into mainstream languages (as you mention), more interesting experimental languages, etc. Aka everything working as intended.
Insofar as it didn't prevent the good parts of FP to become mainstream features, I agree.
But the popularity contest IS important for language emergence. I still believe there would be a place for a functional language that strives to adhere to the principles more stricly, and that programming could benefit from such a language gaining a lot of traction. But, as mentioned before, if such a language requires people to deal with a very different syntax, or applies it's principles too rigidly, it will likely fail the popularity contest.
It also is important for paradigms to become pervasive. As I mentioned, FP has a lot to teach even to OOP people. Writing functional code is a great way to organise a program.
But tell that to a young software developer who has only ever been served enterprise spaghetti OOP pasta with extra abstraction sauce garnished with pseudo-encapsulation cheese, and for whom "functional programming" is something he only saw ridiculed as a meme on some subreddits.
No, popularity isn't the only important thing. But it can help things to reach their potential.
Note that there are many functional languages which don’t care about purity at all: for instance, Scheme, OCaml, SML and Elixir. I get annoyed when people confuse Haskell for the broader paradigm of functional programming. (Even though Haskell is my main programming language!)
But people tend to avoid the name "procedural" at all cost - which is bad because procedural programming really has it's advantages and should be clearly separated from FP which also has certain advantages.
If you declare a function effect-free, and try to perform effects inside it, then you'll get a compiler error.
You are still allowed (and it's common practice!) to declare your functions as effectful.
Unfortunately the 'signal' of this message is often lost in the noise: For every Haskeller happily writing effects, there's 9 non-Haskellers writing that 'Haskell's big mistake was being pure and not allowing effects - you should use X instead'.
Other advantages of pure FP might be thread safety but queues take care of most of this (and often locks are not hard to use). Or low-level compositionality. But as Alan Kay said, what we need are bigger objects. John Ousterhout seems to agree. Re-use in the small increases complexity.
You've selected for the work that you already do.
If you wanted to use transactions, you'd find them impossible, give up and go back to not having transactions.
And once you give up on the impossible dream of transactions, you're back to no problems in practice.
Similar to OOP, which promised to do this by encapsulating state, FP promised to do this via purity, aka. getting rid of as much state as possible, and only allowing stateful transition at certain well defined sections of the program.
The "market advantage" of OOP was that, via Java, it was already so well established, and so many coders had been trained in OOP languages, that it remained alive. FP on the other hand, coming out of academia and requiring all these industry people to suddenly do things in syntactically and conceptually different ways, never really gained traction. OOP simply came first, it is as simple as that.
Whether FP would have actually solved the problem is anyones guess, since it never gained the traction of OOP and Procedural languages. My best guess is that it wouldn't, because I don't believe in silver bullets.
It should be noted that both approaches contributed valueable things to contemporary languages. E.g. first order functions being the norm comes from FP.
Not really. Lisp is a functional programming language and has existed since at least 1960. Some claim there were many other proto-functional languages since the early 60's, and the FP language [1] (a clearly functional programming language and the result of the famous paper "Can Programming Be Liberated From the von Neumann Style?") appeared in 1977 - was inspired by much earlier efforts like APL.
OOP really only became a thing with Simula in 1967, but was not popular until the 1980's with Smalltalk and Common Lisp's Object System (CLOS) came about (so yes, there was a OOP/FP hybrid already decades ago), and then C++ and finally Java much later... at which time Functional Programming languages already included Miranda (1985) which later evolved into Haskell, and Erlang (1986). That is, FPP languages were at least as common as OOP languages by the 80's.
As far as I know, however, pure functional languages were not really very efficient until Haskell came about, while OOP languages were nearly on par with procedural style: which mattered a lot in 1980's machines.
*sight*
Okay, let's dot the i's and cross the t's then, shall we, and include languages used long long before software development became the industry behemoth it is today.
You're right. There, I said it. You are absolutely right.
Many of the concepts of functional programming were indeed pioneered in LISP, and it was indeed specified in 1960, 7 years before Simula.
But hey, let's dot another "i" and correct my statement. Because, FP isn't in contrast to OOP so much as it is in contrast to imperative programming, and all it's mutable state, right?
So, is there an imperative programming language, older than LISP, and still in use today? And the answer is: Of course there is ;-)
No it isn't, because the history relevant for this question doesn't begin at the very start of programming. Most programmers active today didn't go to university in the 60s. In the timeframe relevant to answer this question, the people were indeed confronted with OOP languages, and FP languages were already a niche topic, end of story.
This also coincides with programming, as an activity, massively gaining in popularity across many industries.
Real FP means referential transparency and that started with languages like Miranda and later Haskell.
What many people consider "FP" today is in fact just procedural programming with higher order procedures and lexical closure.
A lot of early FP teaching was done in Lisp. Some kind of "Pure Lisp" was used, which are imaginary subsets of Lisp, restricted to side-effect-free, non-destructive functions.
FP started quite a bit before Miranda.
When you write Lisp, you're mostly composing functions. It's truly very functional, just not purely functional which is probably the motivation behind your refusal to include Lisp in the functional programming language family, which would horrify the founders of the field as it's a simple attempt at redefining a widely used, well understood term to become a small subset of it for reasons of gatekeeping what we should, according to you, include under the term without any real technical reason behind it.
Many functional zealots aim for a purity beyond all reason and comprehension. When what you really want is something like Erlang/Elixir or even C#.
I assume that all of this gets funding because ten years later it makes C# programmers more productive, not because of mass appeal.
With the advance of lifetime analysis, mutable value semantics, and local mutability, there’s no need to ban mutable state outright. The push for functional programming will be waning in regarding to purity.
I've been looking for such a feature for some time. Do I understand correctly that the facts can be established dynamically from, say, IO functions?
Also, are you going to present at FOSDEM?
Also, I agree but I'm not sure what I would propose as a better token. Maybe another colon?
def printAndInc(x: Int32): Int32 \ IO =
becomes:
def printAndInc(x: Int32): Int32 : IO =
Or maybe, since functions need something after the \, even for pure functions, we just drop the \ and use the last argument?
def printAndInc(x: Int32): Int32 IO =
Other languages already have readable keywords in the function definition; extends, raises, where, having, Optional, and so on. They don’t feel unnecessarily verbose.
One thing not clear is what's the reference vs value model, lifetime, and mutable vs immutable model.
Over summer, I built my own little functional language, Crumb (https://github.com/liam-ilan/crumb). Unlike Flix, the scope is tiny, but some pretty awesome stuff has been done with it. (Checkout this pixel art editor in your terminal, 100% Crumb: https://github.com/ronilan/crumbicon).
There’s a template (https://github.com/liam-ilan/crumb-template) and vscode highlighter (https://github.com/liam-ilan/crumb-vscode) for anyone who wants to mess around with it. Any feedback super appreciated :D
This is disappointing. One my main grievances with Go is that it's very difficult to prototype code because it won't compile with unused variables. It massively slows down development. It annoyed me so much that I eventually forked the Go compiler and made a version where unused variables are only a warning.
You’re able to fit more code on a screen, and it’s less visual noise. It’s like Pareto better. I really don’t get why others don’t copy it.
Give me braces and rip a formatter across the whole codebase and be done with it.
Furthermore, I think that the trend of compilers/interpreters caring about whitespace formatting rules should really end. You can't ever force everyone in the world to write aesthetically pleasing code in your language and someone out there will always be able to write a complete trainwreck, and everyone disagrees on what is or is not aesthetically pleasing. Leave the problem up to configurable code linters where it belongs. Let people make "mistakes" (in your eyes) if they want to.
(I am one of the developers of Flix).
Rough edges, but I'm really liking it so far. Let's see how it will handle the upcoming Advent of Code.
Particularly in the sections titled "What features are not supported" (no exceptions or panics, so e.g. indexing has to return an Option in case it's out of bounds) and "What controversial design choices are made". Some pithy remarks towards the end as well.
To follow HN tradition and find the most controversial topic to discuss, my guess is it's either not allowing name shadowing, or divide by zero equals zero. Or the site not working without javascript (see the section on that near the end, but you'll need to turn on javascript to read it I guess)
I'll perhaps be the first to jump on the 1/0 != 0 hate train though; they mention they designed the stdlib to avoid the partial-function pitfalls of Haskell's, but the article they linked to support their design decision of 1/0 being 0 mentions that it boils down to division being a partial function - x/0 is not a case division can handle. Would it not then be reasonable to make division return an Option?
I don't mind the disallowing name shadowing, but I really, really hate (I mean that) websites that are just good ol' text and the odd picture that require Javascript. The excuse of "we used React, it's easy" seems odd given that HTML is much easier.
Make those warnings in debug/test builds, and errors in prod builds.
Any language that does it, is beyond usable (notably go and zig). Like, I would literally fork the compiler before using them with that “feature” on. It’s completely braindead thing to do — like okay, have a separate production release mode and make it an error there. But for quickly testing out stuff, you will inevitably comment something out, which makes a variable unused. Commenting that out will also make something else unused, so you literally have a recursive problem with some random depth, and depending on how deep it goes, you will literally lose all of the context on what you wanted to debug in the first place.
There is literally zero advantage of this idiotic bullshit, my proposed solution of doing it only in prod release gives all the benefits with none of the negatives.
It is a brain-dead feature, verbatim if you prefer that word.
But feel free to give me the nuance to this design issue that you so miss.
It produces warnings for unused variables, and warnings become errors, when you want to compile a production executable with -prod , so you can get both the benefit of prototyping without losing your flow, and you are still required to cleanup after that, when you are finished, before release.
But I agree, this can be cumbersome. So, Flix allows any unused construct to be prefixed with an underscore to mark it as unused. (But underscored things cannot be referenced.) This seems like a pragmatic trade-off.
(I am one of the developers of Flix).
What benefit does it have in development-mode?
(I am one of the developers of Flix)
Inspirations and ideas from four of the arguably most complex languages of the modern world, all the best with that.
These languages put forth ideas that are extremely powerful. They might be unconventional from an imperative programming lens, but to call them all “complex” as a justification for discarding them entirely is pretty shallow.
With the rapid rise of AI, most tasks will soon involve the management of AI models rather than writing code. However, it is still important to have a basic understanding of coding.
Introducing a new programming language at this point seems silly to me.
;)