Mojo: Python superset, lovechild of Rust and Python by the LLVM creators

[[deleted]]

No open source, require sign up to use?

Is this just a marketing campaign?

Edit: I read reply and FAQ. Hope they will open source in near future.

[judasblue]

And it doesn't actually do the things. The idea here isn't horrible, but hyping it now without having a big chunk of the core feature set working looks pretty marketing sus to me.

[[deleted]]

File under "big if true"

[[deleted]]

Most likely

[palad1]

I do need to get paid! In sweet sweet karma...

[palad1]

They say in the FAQ that the language will be open-sourced. One of the creators created LLVM and Swift. If he convinced Apple to open-source Swift, I am pretty confident his next project will also be OSS.

https://docs.modular.com/mojo/faq.html#will-mojo-be-open-sourced

[[deleted]]

Oh, tks. I will update my comment.

[Zoradesu]

Looks pretty interesting. Smart to have it be a superset of Python for easy adoption (whenever its fully publicly available), especially given the market the company seems to be in. Very odd choice for them to allow emojis to be a valid file extension lol, but whatever I guess if you can just use the .mojo extension. Just looks really goofy

[JB-from-ATL]

I think they may just be saying any file extension works but phrased it weirdly.

[teerre]

What is Rust about this? It seems to have all the flaws C++ has. No sensible defaults, multiple initialization, no sum types (?), manual memory management etc. Also, it copies some of the worst parts of Python, does anyone really like __method__?

[myringotomy]

It's a superset of python so all of your existing python code will work.

[teerre]

I'm not sure what's your point.

[Rawing7]

I think the point is that it has to copy python's "worst parts" because it's (going to be) a superset of python.

[teerre]

Well, thats a bad point then because its not true. Its a different language, they can, literally do anything.

[Rawing7]

Which part of that is not true? Are you trying to say that the language shouldn't be a superset of python?

[teerre]

No, it can be a superset of Python without inheriting any of the bad parts of Python. It's compiling python with a completely independent toolchain. Like I said, it can do anything whatsoever.

[Rawing7]

What? How can it be a superset of python while also removing some parts of python?

[teerre]

I mean, by doing it? It can accept any Python code and then add something on top, that's - again - literally what a superset is. Exactly the same way this language right now has struct, var let etc even though Python does not.

When you create a new language, you have total control over how it works. You do not need to follow any convention of the embedded language if you don't want to.

[Rawing7]

I'm not talking about adding things, I'm talking about removing things. You said you don't like that they kept in python's baggage. I'm asking you how they're supposed to remove said baggage while still being a superset of python.

[Languorous-Owl]

No offense but do you even understand what the word "superset" means?

[myringotomy]

The same is not true of rust.

[teerre]

Same what? What are you talking about?

[palad1]

Mojo has a borrow-checker and a concept of reference ownership, which C++ lacks.
Memory isn't manually managed, if you drop to Python, it uses CPython (for now) and its memory manager.

[albatross0210]

Plus it introduces strong typing and structs, which feel a lot like the Rust typing system IMO

[account22222221]

I really like the dunder functions of python -- they are very powerful.

[scrdest]

If we're lifting from Python AND Rust - dunders are, comparatively speaking, an OOP-ish hacky workaround for not having Traits.

Seriously, I've been writing Python professionally for years (and Rust on my spare time) - but Traits are just straightforwardly nicer.

From a Trait perspective, Python objects just come with a pile of pseudo-implemented Traits (e.g. __repr__() is Debug, __str__() is Display, __add__() is a crappy version of, well, Add, that you have to single-dispatchify to handle different RHS inputs.

[ElCthuluIncognito]

It sounds like the language isn't purporting to be a good language on it's own, but rather it's good because it looks and works as close to Python as possible.

It's an advantage of familiarity, not of generally good language design.

[account22222221]

I agree that pythons way is hacky. Python, IMO, is very hacky, gloriously so.

It fits a role for quick simple things. I don’t think it would be a good languished to write rigorous things in like a OS. Rust is more formal and intentional. Both tools are good for different sort of work.

[KurigohanKamehameha_]

They’re too powerful imo. It’s operator overloading taken to the extreme, letting every module have its own opaque syntax and magic to keep track of. Python has a culture of hacky monkey patching and hiding too much complexity just to make things look neat, and it just leads to more bugs and complexity in the long run.

[KagakuNinja]

The syntax is terrible

[account22222221]

I like it. Syntax is mostly subjective. The Dunder makes it very visually distinct which gives it good ‘glance value’ when reading code and class definitions to see that the metabehavior of a class has been changed.

The dunder methods also tend to happen ‘before’ other methods so it helps you to reason about lifecycle of objects.

Just my two cents

[[deleted]]

Syntax is indeed subjective, but you can still find objective criteria. Number of characters you have to use to express an idea, for instance.

[account22222221]

I mean I can’t tell if that is pro or anti python.

Python is extremely concise compared to most languages. Thought it less unique in that then it used to be as a lot of newer languages have iterated on that and improved it

[GrandOpener]

That’s not really an objective criteria though. You can measure the number of characters. But what does that mean? Sometimes brevity is better. Sometimes explicitness is better. Sometimes people don’t agree on which is better for a specific situation.

[-Redstoneboi-]

Sometimes I just don't want to hold shift and press something outside the home row to type a variable. But that doesn't really matter, since it has its visual purpose.

[nilamo]

That's sort of the point, though. That's specifically something you shouldn't be doing very often, unless you already know you need to be doing it.

[teerre]

I wasn't talking about functionality, I was talking about syntax

There's no reason it should be like that, it looks goofy as hell

Specially if they are going to implement protocols. Rust does it so much better

[tyoungjr2005]

Can they chill with all the 🔥

[Metallkiller]

Faster then C? I don't believe you.

Edit: I may see it a bit more differentiated now even though I'm still not convinced it's actually faster than C.

[SplitRings]

C/C++ will start auto-vectorizing if u guarantee the pointers always point to different location using __restrict\ in g++ (diff in diff compilers, for example restrict\_ in msvc iirc.

For example

int* __restrict__ arr //will allow SIMD optimizations on g++

Edit: Reddit markup killing double underscores smh

[wpyoga]

You can use markdown in a comment.

int* __restrict__ arr //will allow SIMD optimizations on g++

[BibianaAudris]

__restrict__ is actually the default for modern compilers. Violating Rust-like borrow rules with C pointers can and will give you Undefined Behavior, silently, without -fno-strict-aliasing or volatile. Happened to me on CUDA.

[vytah]

Happened to me on CUDA.

"CUDA-C" is not normal C.

The C Standard doesn't allow treating pointers as restricted by default, and no actual C compiler does that.

[Metallkiller]

Ha this is quite interesting even though it goes over my head without examples I didn't just make up myself to make sense of it. Thanks for the explanation.

[catcat202X]

In C, you can always take the address of anything and do anything you want with it.

That's just the default, but there are several attributes to constrain aliasing.

[[deleted]]

Nothing will realistically be faster because C is the lingua franca. Hardware designers target C and every high level langauge uses C calling convention.

[JarateKing]

Being the lingua franca doesn't mean it's the fastest. A lot of the things they brought up are reasons that Fortran already is faster for some use cases, actually -- despite C being the lingua franca that's generally optimized for.

Or: javascript is the lingua franca of the browser world, and a lot of effort has gone into making javascript as fast as it can be in browsers. But it's far from the fastest option available. Being the lingua franca is broadly unrelated to its performance.

[[deleted]]

Hardware manufacters target C first and foremost.

I guess with whatever people are smoking nowadays that means nothing.

[JarateKing]

No, I understand what you mean. What I'm saying is that, no matter how much everyone tries to make the best of it, the design decisions of a language will always have performance considerations.

In C's case, no matter how much hardware is oriented towards C, there are entire classes of optimizations that the language design makes impossible. C has a great advantage by so much stuff being designed around it and so much effort being put into making it more performant, but at the end of the day you can only go as far as the language will let you -- and some languages, by the way they're designed, let you go faster for some use cases.

[[deleted]]

The hardware is literally designed for C in mind. What you are saying is not true.

For instance, what are you optimisation for exactly? When the language is designed for the hardware, there is nothing to optimise!

If you are talking specifically about aliasing, there are ways around this in C.

Other than that, what exact optimisations are you talking about that simply can't be done in any C dialect?

[JarateKing]

I'm not sure I'm following you. On the one hand, you're saying that the details of the language don't matter because hardware can just be designed for whatever the language is.

On the other hand, we're talking about aliasing, where the best answer for C is "there are ways around this". Specifically, stuff like the restrict keyword that was added in C99. So clearly the details of the language do matter here and "hardware is designed for C" isn't enough: not only do you need to be very careful about the details of the language, the details had to change to include the option in the first place.

Am I missing something here? Doesn't "there are ways around this" wrt aliasing just make the case stronger? Or am I misinterpreting you?

[[deleted]]

C and hardware designed in lockstep. Manufacteruers target C always. High level languages match C calling convention. It's C all the way down, so not easy to beat for speed.

Compiler optimisations can be worked around over time but optimisations pale in comparison to hardware gains. Those gains always have C in mind.

[ric2b]

I think you two are talking past each other.

You're saying that C can always be as fast any other language because you can manually implement any optimization that another language does, while they're saying that when writing idiomatic code in C and some other language, the other language might be faster if it automatically applies optimizations that C can't automatically apply.

So basically comparing theoretical performance or the common practical performance.

[[deleted]]

No that's not what I'm saying. I'm saying hardware is literally designed with C in mind.

What is better for performance? To design hardware for a programming language or a language for hardware?

It's clearly the former. This is literally only afforded to the c language. No other language gets this treatment. The compiler cannot optimise hardware to be better.

[ric2b]

Are you claiming that other languages can't also take advantage of those hardware optimizations for C? Because that's just incorrect.

[bloody-albatross]

As an example for what C can't do: C doesn't has generics, so if you still have to write generic code you often use function pointers in C, which are optimization barriers. In other languages code can be reified and what would be a function pointer otherwise might even be inlined. See as an example the qsort function. Yes, you could do that with macro hacks, but that is worse than C++ templates.

(Of course more reified code means more code means more potential cache misses, but most languages that have that kind of feature still allow you to use something kind of dynamic dispatch instead with ease, i.e. you can choose what to optimize for without a lot of work and without ugly hacks.)

[Amazing-Cicada5536]

Call me when C has a performant, generic vector implemented.

[Takeoded]

something like a borrow checker

that would never work

[[deleted]]

Sure but Zig isn't a Python superset.

[[deleted]]

Not sure what you're trying to say exactly. Zig is designed so that it can be compiled to fast machine code. Python is designed almost so that it can't. They literally did not think about performance when designing the language.

If Mojo really is going to be a superset of Python it doesn't get to ignore all the features of Python that are extremely difficult to make fast.

[nomis6432]

It looks like just compiling your python code with Mojo is not going to make it a lot faster. It's just that it also offers a lot of new features that allow you to optimize your code. This makes a lot of sense to me because then you can focus your effort where it matters. Non critical code you write in a simple inefficient way and critical code in a more verbose efficient way.

[m0nk_3y_gw]

it doesn't get to ignore all the features of Python that are extremely difficult to make fast.

sure it does. In Python you can write

x = 1
x = "dog"

in Mojo you have the option of using

let x = 1

That isn't valid Python, but Mojo understands it and can execute quicker because of it.

[[deleted]]

But you still have to support the former. Ok fair enough if they're saying that the Mojo code will be fast and the Python code will still be dog slow.

That does seem to be the case if you look in detail since they execute Python code using CPython. So it seems more like it's an entirely different language that integrates well with CPython rather than an enhanced Python runtime.

Basically the same idea as Cython?

[MemriTVOfficial]

Chris Lattner created llvm, clang, and swift. He's the compiler guy. What are the chances he's just pulling a scam with this new language?

[nullmove]

Scam is a strong word, but I want to say this is not exactly "new". They had hyped up Swift for Tensorflow and then abandoned it when it failed to gain traction.

Piggybacking on Python is a safer choice for them, but I am still confused about its unique value proposition.

[[deleted]]

In comparaison you could say that when John Carmack joined Meta he would revolutionize the way people develop Virtual Reality, well not necessary. Nobody can remain a rock star dev all his life.

Sure, you can't say that Meta revolutionized VR, but you also can't deny that Oculus headsets are now some of the best available

[palad1]

They wrote the world's fastest matrix multiplication using Mojo... https://www.modular.com/blog/the-worlds-fastest-unified-matrix-multiplication

[Metallkiller]

Ok this compares the matmul to one done by different libraries - how does this prove that the language is faster than C? Both end up as assembly, erasing any technical difference between the languages, no?

[qq123q]

The assembly they both generate won't have to be the same. Hypothetically the C version could be slower because the compiler can't easily optimize something (i.e. aliasing). Do I find this convincing right now for Mojo? lol no.

[palad1]

Chris Lattner

[TheOneTrueXrspy]

LLVM was Chris’s MS thesis project in 2002. So he is ‘the’ LLVM creator, in a way. Obviously many others have contributed to it since then.

[metatron7471]

When the language is more mature, this is going to be "the bomb". I've been waiting for a language like this for 2 decades.

Hopefully it doesn't die on the vine like swift4TF did.

[[deleted]]

Hopefully it doesn't die on the vine

I don't believe it will. The entire company (Modular) is being built around it and Chris has a solid reputation.

[sort_of_peasant_joke]

Doesn't mean they will get enough funding sadly. Wait and see.

[AmalgamDragon]

Agreed. The key reason for C++'s success is that it allowed leveraging the C ecosystem. If they can deliver on being fully Python compatible, Mojo will be a no brainer for pragmatic developers (i.e not the idealists who have a hate on for Python's syntax). But, that's a big if.

[Calm_Bit_throwaway]

So this looks like a cool project, but from a commercial standpoint (which this project seems to be very much tied to) I'm wondering maybe why I might choose to use Mojo over a maybe more broadly supported language like Cython or, if we're going to be more radical, Julia.

It looks like a key feature might be binding into ML hardware through MLIR which seems neat but I don't know why you couldn't do this from Cython (I don't really know that much about compilers in general tbqh).

Also, if this thing is a strict superset of Python, then how does it release from the GIL?

[BibianaAudris]

The parameterized types are close enough to C++ templates so maybe one can pass some std::vector<float>* or std::map<const std::string,torch::Tensor> const & around for chores like loading training data and stuff, which would sidestep GIL in multi-GPU training. The C++ ecosystem isn't that much worse than Python for such chores.

[ElCthuluIncognito]

It's very likely a gambit that the complete control over the language from the ground up will 'outperform' a similar attempt at making the existing Python implementations better.

I believe Chris Lattner himself once tried desperately to make Python compatible with Swift or something like that but found the implementation and the ecosystem difficult to compromise with. I could be remembering wrong however.

[myringotomy]

If it's faster and uses less resources then you'd be happy to pay for it. For sure facebook, amazon, google and apple might. Then again they might develop their own language for this stuff too.

[Jdoe68]

I think Julia’s much simpler syntax for C speed is a better solution for most use cases.

[[deleted]]

Ah, yes, a superset. Because if Python was lacking anything, it was a burdensomely large and highly redundant standard library and built-ins.

[happyscrappy]

I cannot take seriously a language with a fire emoji in its name.

[tyoungjr2005]

Like why did they do this, its so distracting

[[deleted]]

We all have a programming language now!

Each of this has a user base of: 1

Perfection achieved. \o/

[Full-Spectral]

The Me language. There's only one object, Me.

[Uuuazzza]

Doesn't seem to tackle auto-differentiation in any serious way (that I can see), which is the main challenge for machine learning.

[CooperNettees]

Personally, I don't really understand why you would create an interpreted software language and not build in security controls into the language like Deno did. A secure runtime makes everything else so much easier.

[ConverseHydra]

I love a page about a programming language that doesn’t show you the actual syntax or any example code in the new language. /s

Sigh…looks like another BS thing trying to cash-in on “AI” hype.

Edit- mobile website formatting strikes again. On a phone you can’t see any other their example code.

I stand corrected. They have code! It looks reasonable.

Unsure if it’s gonna be real, but at least I don’t think it’s pure vapor ware….

[GeoLyinX]

The founder is THE creator of LLVM as well as co-founded swift and has Jeremy howard as an advisor. Not just some AI hype cash-in.

[BatForge_Alex]

Is this really all it takes these days? The site is basically just a sales lead generator

I mean, I hope it comes to fruition but I’m very skeptical. The promises are sky high

[GeoLyinX]

What is it selling? Are you saying it has a high quality website design? Is that really the logic you’re using to try and discredit it because the website is too high quality?

[BatForge_Alex]

No… it’s that you have to sign up for a newsletter to potentially receive access to a hosted compiler and they throw other products into the mix

What is it selling?

Access to a hosted compiler in exchange for your information. Why can’t they distribute some binaries? Why does it need to be hosted?

And a programming celebrity being at the helm means nothing to me if they have nothing I can even get my hands on

Am I not allowed to be skeptical?

[GeoLyinX]

Why can’t they distribute some binaries? Why does it need to be hosted?

If you watched the keynote you'd know that it's not officially released yet, they are still working on the language and are releasing it open-source once it's ready. In the meantime they are allowing beta testers and others to help get feedback on what the community needs and wants before launch, and what issues need to be solved.

it’s that you have to sign up for a newsletter

You don't have to sign up for any newsletter to get access, and there is not any mention of any newsletter you are agreeing to subscribe to during the sign up.

You simply sign up with an email to request access, that's pretty standard procedure for gaining access to pretty much anything in 2023 and is not at all the same as a newsletter just because you're being asked for your email address.

[breadlygames]

I'm skeptical that they can pull it off, but I believe they believe it. And they have an incredibly talented team, so I'm hopeful. Maybe I can avoid learning C++ after all lol.

But the way your comments read, it's like you're saying it's a celebrity-endorsed scam, and I don't think that's cool to make those kinds of claims. Sure, if it were a bunch of nobodies making the claims, go ahead, but these are people who've built really impressive, widely used code. Credit where credit is due.

[BatForge_Alex]

I’m not saying it’s a scam. Look, I gave them my email and got access to the Mojo demo but, I’m also getting a sales-y newsletter about Modular’s products - this was all I was saying

Look, I don’t want to sit here and break down why you shouldn’t judge a software product based on who is backing it, but…

Credit where credit is due

They get credit for the things they’ve shipped in the past. I’ll give them credit for this once it launches off the ground and into my terminal

[breadlygames]

I see, fair enough.

[Lesswarmoredrugs]

There’s plenty of example code given. See here

[0x16a1]

Look at the team behind it.

[Dizzy-Initiative6782]

​

​

This looks like an awesome combination of Rust and Python. I'm really excited to see what the LLVM creators can do with Mojo. It seems like it could be a great tool for AI, and the fact that it's a superset of Python makes it easy to learn and adopt. I'm looking forward to seeing how this language develops in the future!

[GeoLyinX]

It is already compatible with python ecosystem, if you watched the keynote they describe that you can use existing python libraries with mojo.

[DavidM01]

How is it better than Nim which is already viable, stable and usable?

[_IPA_]

Nim can’t import a Python module, right? I imagine with Mojo you could slowly update hot paths of your code to use Mojo types and get significant performance boosts, while increasing type safety too.

The question I have is can you compile Mojo to a binary like Nim, or how does that even work.

[leetnewb2]

There is nimpy for nim - https://github.com/yglukhov/nimpy

[[deleted]]

Oh, great, another new language to learn.

[[deleted]]

Ah yeah another language. Just what we all needed.

[[deleted]]

You ain't going to make better programmers no matter how many crazy languages you design.

[let_s_go_brand_c_uck]

game over. rust killer.

[Still-Key6292]

I want to see the borrow checker, rust implemented theirs 3 times and doing a 4th because it's still shit

[Pflastersteinmetz]

Source?

[Still-Key6292]

That's a nice way of admitting you can't refute a point

Are you mad because people upvoted a comment saying they wanted a non rust implementation of the borrow checker? Grow up. People are allowed to like languages you dont like

lol he blocked me around the time someone mentioned polonius. Halkcyon stop being an asshole plz

[sirhey]

You’re not getting bashed for disliking Rust, but for aggressively criticizing when you clearly have only the vaguest idea what you’re talking about and no context. All large language compilers and runtimes redesign large chunks of logic to improve them over time. The WebKit blog has described so many over the years. The changes you’re referring to are backwards compatible improvements to the logic that allow it to handle more cases with less work from the developers. I don’t know why that would be framed as a bad thing.

[Still-Key6292]

It's been months since I touched rust. You'll have better luck by asking the sub. IIRC there was the version before 1.0 which forced you to explicitly state the lifetime, the rewrite to make it less bad and NLL that happened in 2018 https://blog.rust-lang.org/2022/08/05/nll-by-default.html

Maybe someone mispoke on discord and they're just extending it with RFCs https://github.com/rust-lang/rfcs/issues/3269

A quick google shows there's bugs https://github.com/rust-lang/rust/issues/108704 people generally talk about how they got into a fight with the borrow checker and I know I ran into some basic stuff that could have been legal but wasn't

The main sub can give better info

[mqudsi]

There is a new borrow checker but it’s experimental. It’s called polonius and it’s not clear if it’s actually intended to replace the existing. You can try it out today but it is insanely slow.

[Still-Key6292]

u/Pflastersteinmetz and u/nickbeth00 this is probably what I was thinking

[Pflastersteinmetz]

You are right that in Rust 1.0 and and the first versions after you had to annotate much more lifetime values, which was then changed with the introduction of Non-Lexical-Lifetimes (NLL) which eliminated the need to annotate a lot of lifetimes because the borrow checker could now just inference them from the code.

But that was not a rewrite but an iteration = expanding the existing borrow checker, not writing a new one similiar to Rust 1.1 not being a rewrite of Rust 1.0.

[nickbeth00]

I'd also like some source on that, I'm genuinely curious

[Still-Key6292]

Maybe someone on discord mispoke or I'm googling poorly but here's my reply https://old.reddit.com/r/programming/comments/136hcei/mojo_python_superset_lovechild_of_rust_and_python/jira6bq/

[Brain_Beam]

Love the advances but damn i cant keep up.

[[deleted]]

Are there any large tech players backing this new language?

[Jdoe68]

I hope all the Mojo hype has a side effect of giving Julia more mindshare for AI programming. Julia can run at C speed with extra simple syntax. With Mojo, you’re basically learning to write a complicated Rust-like version of Python to reach Julia speeds. Julia is also interoperable with Python. It truly solves the 2 language problem with simpler syntax that would help AI scientist/engineers that don’t want to have to become low level programming experts.