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The Mojo language (by Modular, now Qualcomm) is now open-source

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Re: The Mojo language (by Modular, now Qualcomm) is now open-source

#71

Post by snovymgodym »

ameliaquining wrote: post #60
melodyogonna wrote: post #51

If you like C++, you're going to like Mojo (if you're looking for alternatives). Some of the semantics and designs are inspired by C++, but wrapped in a Python-like skin. The way to think about Mojo, when compared to Rust, is that it was designed by expert C++ programmers as what they imagine a good C++ will look like. When I see Rust, I see designers who loved the functional programming paradigm and wanted to make a…

Can you explain this in more detail? I'm not really familiar with Mojo but I can't think of obvious ways in which Rust's semantics (as opposed to syntax) are more functional than C++'s.

Rust's type system is very Haskell/ML inspired, specifically the first class support for algebraic types and pattern matching.

Modern C++ has come a long way with typed optionals and variants, but it's very tacked-on and lacks the safety guarantees and ergonomics of a language designed with this paradigm at a fundamental level.

Re: The Mojo language (by Modular, now Qualcomm) is now open-source

#72

Post by saghm »

verdagon wrote: post #61
melodyogonna wrote: post #51

If you like C++, you're going to like Mojo (if you're looking for alternatives). Some of the semantics and designs are inspired by C++, but wrapped in a Python-like skin. The way to think about Mojo, when compared to Rust, is that it was designed by expert C++ programmers as what they imagine a good C++ will look like. When I see Rust, I see designers who loved the functional programming paradigm and wanted to make a…

This isn't quite accurate; Mojo uses the same memory safety approach as Rust. It has some mutable aliasing, but only intra-function, so in practice programs will be pretty much Rust-shaped.

Their comment seems to be mostly focused on surface-level syntax from what I can tell (e.g. "wrapped in a Python-like skin"; "what they imagine a good C++ will look like"). Rust code probably does resemble functional languages to someone who uses C++ primarily, and Mojo doesn't resemble them as much. I don't find that to be a particularly enlightening insight, but I have to imagine that the syntax of Mojo is one of the first things that will catch people's attention, so it's not surprising to me that it's something that people will have a lot to say about.

My hot take is that what a good C++ will act like is basically just already Rust, mostly because the main problems with C++ can only be solved by taking away some of what makes it C++ in the first place. Some C++ developers will probably not be happy with a language that takes away the parts they still want to use, but others might just not like what Rust "looks like", so if dressing up the same Rust semantics in a new skin ends up getting the world more code written without the bad parts of C++, that's probably a good thing.

Re: The Mojo language (by Modular, now Qualcomm) is now open-source

#74

Post by ameliaquining »

vovavili wrote: post #67
ameliaquining wrote: post #64

Earlier quoted context omitted.

Has that ever happened to a programming language?

Darklang is probably the closest thing that comes to mind - https://blog.darklang.com/goodbye-dark-inc-welcome-darklang-...

This was caused by the company running out of money, not by investor pressure, and it resulted in the language becoming more open rather than less. So it doesn't seem like an example at all.

Re: The Mojo language (by Modular, now Qualcomm) is now open-source

#75

Post by saghm »

snovymgodym wrote: post #71
ameliaquining wrote: post #60

Earlier quoted context omitted.

Can you explain this in more detail? I'm not really familiar with Mojo but I can't think of obvious ways in which Rust's semantics (as opposed to syntax) are more functional than C++'s.

Rust's type system is very Haskell/ML inspired, specifically the first class support for algebraic types and pattern matching. Modern C++ has come a long way with typed optionals and variants, but it's very tacked-on and lacks the safety guarantees and ergonomics of a language designed with this paradigm at a fundamental level.

So what does this actually translate to in terms of Mojo? Rust has algebraic types and pattern matching, C++ has some specific use cases that are "tacked-on", to use your phrasing, so when the parent comment says that Mojo is what a good C++ would look like, they're saying...it doesn't have algebraic types, or that they're tacked on? It's not clear to me why that would be a selling point, so giving the parent commenter the benefit of the doubt, I don't think this sounds like what they were trying to say.

Re: The Mojo language (by Modular, now Qualcomm) is now open-source

#76

Post by saghm »

ameliaquining wrote: post #66
bwfan123 wrote: post #63

Earlier quoted context omitted.

> expert C++ programmers as what they imagine a good C++ will look like Mojo looks nice but with coding agents the landscape has shifted at least in my view. There is no need for DSLs and abstractions that reduce human cognitive load. So, I still struggle with the usecase for Mojo. If you want close to metal performance, code in something that touches metal (c,c++), and doesnt abstract you away from it or require uns…

I'm confused, C and C++ do require unsafe primitives? I think I must be misunderstanding your comment somehow.

It sounds like they were saying that they think you shouldn't have to use a language primitive like `unsafe` to be able to do the stuff that C/C++ does. (To be clear, I completely disagree with this viewpoint, because I don't think there's any evidence at all that agents won't struggle with the same fundamental problems in writing C/C++ that humans do, but I think it's what they're saying).

Re: The Mojo language (by Modular, now Qualcomm) is now open-source

#77

Post by LoganDark »

saghm wrote: post #55
joshuakelleyds wrote: post #40

I would add quick note to this as title is misleading * It was partially open-sourced before this. There were a lot of cool things they open sourced before like MAX for large scale LLM serving which was outperforming VLLM, Dynamo, etc on a lot of models. (super valuable GPU kernels). This is why Qualcomm acquire them imo. * Chris (also created swift) talked in the past the reason for not fully open-sourcing was more…

> Chris (also created swift) talked in the past the reason for not fully open-sourcing was more because he wanted to get all the core design decisions right. He said this was a big thing Swift got wrong as it scaled too quickly being fully ope source at I don't understand what open source has to do with this. People being able to see your source code doesn't somehow prevent you from changing it however you want. Yes,…

Do you remember how long it took Python 2.7 to die after Python 3 came out? Years. It was horrible.

Re: The Mojo language (by Modular, now Qualcomm) is now open-source

#78

Post by saghm »

LoganDark wrote: post #77
saghm wrote: post #55

Earlier quoted context omitted.

> Chris (also created swift) talked in the past the reason for not fully open-sourcing was more because he wanted to get all the core design decisions right. He said this was a big thing Swift got wrong as it scaled too quickly being fully ope source at I don't understand what open source has to do with this. People being able to see your source code doesn't somehow prevent you from changing it however you want. Yes,…

Do you remember how long it took Python 2.7 to die after Python 3 came out? Years. It was horrible.

I don't understand the point you're trying to make. Are you claiming that if Mojo was open source earlier, everyone would still be using the old versions for a long time? I don't buy the claim that a pre-1.0 language only a few years old without widespread production use is comparable to one of the most widely used languages on the planet that had been around for close to two decades at the time of what you're describing.

Even if I did think that was a comparable precedent, that still doesn't address the more direct point I made about marketing the language at all if this was a concern. What does being closed source do to prevent people from running old versions of a compiler to avoid updating their code?

Re: The Mojo language (by Modular, now Qualcomm) is now open-source

#79

Post by augment_me »

aeonflux wrote: post #3

Does this project have any meaningful traction? Seemed like a cool idea, but I wasn't even sure what problem does it solves. Looks like its completely missing from the regular discussion / news outlets. Every 1-2 years some barely visible post/article reminds me it even exists...

I found that a big issue with it in practice is that the numbers are just not great, and the repo is very vibe-coded. When the numbers are great, it's sometimes cheating with the setup. For example some GEMMs only compute each 8th value and reach close to peak TFLOPs because of this, but it's a vibe-coded reward hack and the verifier does not check all numbers of the target.

Also, compilers have a lot to prove in 2026. Why not just hill-climb a Triton or Cuda kernel if you need perf?

Re: The Mojo language (by Modular, now Qualcomm) is now open-source

#80

Post by ajb »

joshuakelleyds wrote: post #40

I would add quick note to this as title is misleading * It was partially open-sourced before this. There were a lot of cool things they open sourced before like MAX for large scale LLM serving which was outperforming VLLM, Dynamo, etc on a lot of models. (super valuable GPU kernels). This is why Qualcomm acquire them imo. * Chris (also created swift) talked in the past the reason for not fully open-sourcing was more…

Has the title changed since you wrote this? It doesn't seem misleading to me. Misleading would be if it still wasn't fully open source. "It was partly open before" doesn't seem like it's worth a big warning. But that's just my impression FWIW
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