Is Mojo being a superset of Python still part of its projected feature set?
I tried Mojo a bit early on and decided to come back to it when it was more complete, and in the interim I read some comments somewhere that the superset-of-Python part was being walked back from.
On https://mojolang.org/docs/roadmap/ it's stated (Phase 3) that "Mojo may or may not evolve into a full superset of Python, and it's okay if it doesn't."
I feel like that "full superset of Python" part was part of the appeal of Mojo.
Personally I'm kind of tired of 97% python-compatible this-and-that. Python itself has enough of a history of incompatibility and the cognitive overhead in switching might be easier with just moving to a totally different language. But maybe not — it depends on the details I guess.
Honestly reading through the documentation more and more I'm more and more confused about what the 1.0 release actually means.
I feel like this language would really benefit from some sort of 1-pager overview.
I just spent a fair bit of time on the official site, and I still don't think I have a very good grasp of what problem this language aims to solve, or why I would select it over other similar languages
Having written a lot of Mojo over the last two year, just for fun, it's a really cool language. Ownership model adjacent to Rust, comptime in the realm of Zig, rich type system, first class SIMD support, etc.
Performance wise it's the first language in long time that isn't just an LLVM wrapper. LLVM is still involved, but they are using it differently than say, Rust or Zig.
Very excited for Mojo once it's open sourced later this year.
> LLVM is still involved, but they are using it differently than say, Rust or Zig.
Chris Lattner said in a Developer Voices podcast interview:
"Swift in a way was syntactic sugar for LLVM, at the very bottom of the stack it could talk directly to LLVM primitives. Mojo does basically that same trick, but it supercharges it by moving to this MLIR world."
I felt the same way, even after browsing around on the website, and somehow I got to https://mojolang.org/docs/manual/quickstart/, which brings you to mojolang.org instead, which is the real website of the language it seems, instead of "Modular" which I guess is the business.
https://mojolang.org is a lot better as a introduction to the language for a programmer, at least for me, compared to whatever I could find on the modular.com website.
It's supposed to be (currently) a fully native, Python-like language, but for GPUs primarily. Though I am seeing it as having a future as a fully native Python alternative that might get interesting.
I hope with 1.0 (havent fully read the article yet) they stop breaking language features / syntax because they did quite a few different changes over time, their overall goal is to be a fully native superset of Python.
I do see this one overtaking Nim over time, which kind of saddens me, because I like Nim for what it is, but Mojo trying to be a superset of Python is a no-brainer for most Python developers. Reminds me of how a lot of Go devs were former Python devs not C++.
I mean, it feels like "Python, but aiming at a completely different vertical that values native compilation and a borrow checker"? Which is not quite the same thing
Nothing but respect for Chris, and I understand why founders take these deals. But an acquihire usually means the product is the part that gets left behind, and that's the part I cared about.
> Finally, we will continue to progressively open-source more of the Mojo language, as well as components in MAX that we have built with it. Our commitment remains unchanged – we will open source the Mojo compiler and toolchain in 2026.
> Weird to release 1.0 without it. What are they waiting for?
Hmm, I've been under the impression that at one point they said it'd be 100% FOSS by the time 1.0 hits, but maybe I misunderstand/misremember the details. But I remember they'd said it'd be FOSS in connection with 1.0, seems weird to do it this way instead of waiting until it's all FOSS then cut 1.0.
I think they are waiting for a wild success in adoption, and if that doesn't happen they can use the IP to pivot to something else without giving the core away to anyone for free/as open-source.
C and C++ were closed source for quite some time, they still are in places like commercial embedded OSes and console dev kits, even when they happen to be GCC and clang forks nowadays.
Clang actually has replaced most GCC forks exactly because vendors can keep the fork closed source.
Sure but at those times C and C++ had no immediate replacement, and if you were doing embedded C/C++ was your only option.
The same cannot be said for Mojo.
The C compiler source came with the AT&T UNIX tape ... it wasn't open source because FOSS didn't exist at the time and it was under a proprietary license, but it was not "closed source". Parts of MOJO, OTOH, are closed source because the source has not been released (yet ... it apparently will be later this month).
I know right? Would be better to have a banner with the language logo than some totally out of place aislop image, almost makes you think this is a random person's blog and not the official Mojo site
I believe Mojo has been primarily using AI-generated imagery of its mascot for several years now, which politically aligns with its pivot to being a language for AI development.
They’ve had this branding for some years, at least since 2023. I doubt at that time it was fully AI generated, although I have no proof of it. I always looked at it as being heavily AI inspired.
Isn't Mojo expressly for building AI frameworks? It isn't really needed or special as a language by-itself. It's main purpose is to make it easier to program these high end graphics cards for AI.
> Finally, we will continue to progressively open-source more of the Mojo language, as well as components in MAX that we have built with it. Our commitment remains unchanged – we will open source the Mojo compiler and toolchain in 2026.
Why not now though? Why wait for 4 more months? What magic is there to hide in just making it source available at least.
Ladybird is Open Source and doesn't accept outside contributions any more same with sqlite and many other projects. Lots of Google's oss projects also are not very open to contribution.
At this point I find it deeply troubling that it isn't open source. I respect Chris I know folks who have worked with him and but at the end of the day I feel too weird about this entire closed source programming language thing.
If we complain to Nvidia about there weird closed source limitations, I think Mojo is just as bad. You don't even know what your compiler might be doing, and if it does something wrong you can't fix it, you now have to file a bug and wait until the gods from above come to your rescue.
I have had similar issues with drivers, I have faced soo many driver bugs in my work and the answer is always write more code that works around it somehow, this warp level is bad, this feature doesn't work with these values, etc. etc. Why can't I fix them, I have often on Linux just pinged the Mesa team about driver bugs with a rough draft of a patch and gotten it fixed, I can even patch and run it myself when I am in a hurry.
I feel like atleast making stuff, source available like Unreal should be the baseline for any "core" software where a bug could possibly be a major blocking issue for a developer. Windows and Mac are very bad with this.
Mac's CoreML has had soo many bugs over the last couple years I have had to email someone I know at the company to get them fixed or try to get into contact with someone.
Intel's drivers have had bugs too but I have had more contacts there which is a wash. AMD well it's AMD...
Either way closed software sucks I don't want to use fully closed stuff unless I don't have a choice people can make what they want of it. I don't really care.
They kind of did. It has a separate website now [1] . All the docs, announcements, roadmap, some comparisons as you asked are there. So they do seem to be working towards separation.
> They should show some performance comparisions between PyTorch and Mojo, PyTorch+kernel compilation + Triton vs Mojo, ThunderKittens vs Mojo.
The fact that they release 1.0 without doing this, I think says a lot. I personally haven't even started looking into Mojo because of the closed source stuff, but usually you can tell what's going on by looking for what's obviously missing.
Aren’t they already separated? Max is an inference runtime, written in Mojolang, which uses the MLIR compiler chain to target diverse accelerator hardware.
The premise of Mojo used to be that it was a superset of Python so in theory LLMs would benefit from that but I'm not sure how much divergence there's been
Creating a new language in the age of AI seems kind of pointless. I don't write code by hand anymore, I only review it and I prefer it to be in a language which I already know since investing time in learning another language doesn't make sense at this point.
And Mojo will die because nvidia is not interested in maintaining any semblance of backwards compatibility when it comes to CUDA. It's going to be a perpetual race forwards, and whenever nvidia upgrades CUDA, you're going to be stuck there twiddling your thumbs and waiting for Mojo to become compatible.
Additionally, anyone who has seen how Swift evolved should be wary of Lattner saying "the language is mostly stable", or even "the language is released".
It's not true that Nvidia doesn't care about CUDA backwards compatibility. The invention of TileIR was motivated entirely by that problem. GPU architectures are supported by the full tool suites for at least 10 years by CUDA (that's longer than they are for graphics).
Nvidia is also a major contributor to MLIR, which they use for TileIR and ClangIR, so should a compatibility break occur it wouldn't be entirely up to Mojo to fix it.
I tried Mojo a bit early on and decided to come back to it when it was more complete, and in the interim I read some comments somewhere that the superset-of-Python part was being walked back from.
On https://mojolang.org/docs/roadmap/ it's stated (Phase 3) that "Mojo may or may not evolve into a full superset of Python, and it's okay if it doesn't."
I feel like that "full superset of Python" part was part of the appeal of Mojo.
Personally I'm kind of tired of 97% python-compatible this-and-that. Python itself has enough of a history of incompatibility and the cognitive overhead in switching might be easier with just moving to a totally different language. But maybe not — it depends on the details I guess.
Honestly reading through the documentation more and more I'm more and more confused about what the 1.0 release actually means.
It seems like a deliberate pivot towards creating an AI-era language which make GPU programming as easy as writing Python.
I just spent a fair bit of time on the official site, and I still don't think I have a very good grasp of what problem this language aims to solve, or why I would select it over other similar languages
Very excited for Mojo once it's open sourced later this year.
Chris Lattner said in a Developer Voices podcast interview:
"Swift in a way was syntactic sugar for LLVM, at the very bottom of the stack it could talk directly to LLVM primitives. Mojo does basically that same trick, but it supercharges it by moving to this MLIR world."
Why? Because it uses MLIR? Rust has its own MIR, it's even more not-LLVM-wrapper.
https://mojolang.org is a lot better as a introduction to the language for a programmer, at least for me, compared to whatever I could find on the modular.com website.
I hope with 1.0 (havent fully read the article yet) they stop breaking language features / syntax because they did quite a few different changes over time, their overall goal is to be a fully native superset of Python.
I do see this one overtaking Nim over time, which kind of saddens me, because I like Nim for what it is, but Mojo trying to be a superset of Python is a no-brainer for most Python developers. Reminds me of how a lot of Go devs were former Python devs not C++.
Much better options out there. Python already has libraries like Pydantic that offload performance to functions written in Rust under the hood.
The alternatives would be stuff like CUDA
Hmm, I've been under the impression that at one point they said it'd be 100% FOSS by the time 1.0 hits, but maybe I misunderstand/misremember the details. But I remember they'd said it'd be FOSS in connection with 1.0, seems weird to do it this way instead of waiting until it's all FOSS then cut 1.0.
Make of that what you will.
Clang actually has replaced most GCC forks exactly because vendors can keep the fork closed source.
It was just a different culture. There was no expectation that everything should be free.
AMD/NVIDIA/Intel now having first class support for Python DSLs or GPU JITs for their APIs, and Julia as well.
Lastest OpenCV 5 release notes also had a lot of LLMisms.
I guess that's the new normal. Still, I am very hopeful for Mojo.
Did they think that image would make them look fun or interesting? Because it's exactly the opposite.
Yes, so basing confidence on it is totally bogus. Such comments are cheap and add nothing to the discussion of Mojo reaching 1.0 status.
So maybe an AI image isn't the worst.
Why not now though? Why wait for 4 more months? What magic is there to hide in just making it source available at least.
That's the favorable interpretation, atleast.
At this point I find it deeply troubling that it isn't open source. I respect Chris I know folks who have worked with him and but at the end of the day I feel too weird about this entire closed source programming language thing.
If we complain to Nvidia about there weird closed source limitations, I think Mojo is just as bad. You don't even know what your compiler might be doing, and if it does something wrong you can't fix it, you now have to file a bug and wait until the gods from above come to your rescue.
I have had similar issues with drivers, I have faced soo many driver bugs in my work and the answer is always write more code that works around it somehow, this warp level is bad, this feature doesn't work with these values, etc. etc. Why can't I fix them, I have often on Linux just pinged the Mesa team about driver bugs with a rough draft of a patch and gotten it fixed, I can even patch and run it myself when I am in a hurry.
I feel like atleast making stuff, source available like Unreal should be the baseline for any "core" software where a bug could possibly be a major blocking issue for a developer. Windows and Mac are very bad with this.
Mac's CoreML has had soo many bugs over the last couple years I have had to email someone I know at the company to get them fixed or try to get into contact with someone.
Intel's drivers have had bugs too but I have had more contacts there which is a wash. AMD well it's AMD...
Either way closed software sucks I don't want to use fully closed stuff unless I don't have a choice people can make what they want of it. I don't really care.
I care much less about just foss.
Am I understanding the current state of things correct?
They should show some performance comparisions between PyTorch and Mojo, PyTorch+kernel compilation + Triton vs Mojo, ThunderKittens vs Mojo.
1. https://mojolang.org/
The fact that they release 1.0 without doing this, I think says a lot. I personally haven't even started looking into Mojo because of the closed source stuff, but usually you can tell what's going on by looking for what's obviously missing.
This gave me a chuckle. When I think of languages evolving their standards, I do think of C++. But not, you know, in a good way.
But I hope they succeed, it's a very interesting approach. Then I will jump on it later on. S
awesome
(And now in the age of LLMs, the barriers to get started with a new programming language are lower than ever)
Additionally, anyone who has seen how Swift evolved should be wary of Lattner saying "the language is mostly stable", or even "the language is released".
Nvidia is also a major contributor to MLIR, which they use for TileIR and ClangIR, so should a compatibility break occur it wouldn't be entirely up to Mojo to fix it.