One of my favourite features of Mojo is linear types and how deeply they have been integrated into manual memory management - see:https://x.com/melodyogonna/status/2085089269484343725?s=20.
When I first learned about linear types, my first thought of the use case was making manual allocations and deallocations safer without sacrificing usability, but I didn't know what that could look like; now I do. This is great because in Mojo, pointers are surfaced a lot more than in, say, Rust, but such sharp tooling in a language you expect to be safe by default can be problematic. Linear types, combined with the origin system, give the language a lot of flexibility; it is like using a sharp tool with a safety glove: the tool isn't any less sharp, but the chances of accidentally injuring yourself are reduced.
mrbonner 16 hours ago [-]
So I think the permissive license like Apache 2 without opening up for upstream contributions would be the way of future open source development. In a very similar way of SQLite. It definitely will help shield off a bunch of AI generated contributions first and foremost and then, aligning mental model with the human contributions with Mojo leader team.
SwellJoe 15 hours ago [-]
As long as it was proprietary, I could ignore it. Now, I guess I have to learn a little something about it.
setopt 16 hours ago [-]
Very exciting. Closed source was one of the main things making me not try it out yet.
Any good resources for getting started? And anything on doing NumPy/SciPy-like stuff in it?
you can but through a python interpreter in the mojo process so you get the same numpy speed with mojo<->ptyhon interop overhead.
NuMojo is native and also is now starting to support features that numpy can't really do like native GPU execution.
vovavili 14 hours ago [-]
I wonder if the Python-to-Mojo overhead is significant enough where language-native bindings make more sense. I'd be interested in seeing some benchmarks.
melodyogonna 17 hours ago [-]
Such an exciting time for Mojo, I don't think people realize just yet the innovation being brought to fore here.
vovavili 17 hours ago [-]
The innovative potential of Mojo would be constrained to relatively niche and senior dev circles until they get a Windows release, which probably won't happen anytime soon. Python keeps the throne for now.
melodyogonna 13 hours ago [-]
I don't understand this premise. And the more I think about it, the less sense it makes. On the grand scale of things, Windows is the niche platform here. For consumer desktop use cases, it is king, but nobody deploys on it for the use cases that the first version of Mojo is optimised for.
10 hours ago [-]
Conscat 14 hours ago [-]
In the category of AI/HPC software Mojo aims to displace (which is my industry), I don't know many people who care that much about running Windows. The software I work on may only run as a Docker image or directly in a Linux/WSL. Mojo is hardly the only tool in the space (currently) lacking Windows support.
vovavili 14 hours ago [-]
I'd put you in the "relatively niche and senior" bucket without even thinking.
Conscat 8 hours ago [-]
Senior is the last word in use to describe myself as a developer, personally, and I think it's hard to overstate the current economical significance of this software niche. Granted that it IS a niche and nobody would recommend Mojo for, say, kernels in video games or art editors.
a_shiine 13 hours ago [-]
I would put you in the clueless bucket without even thinking
dloss 16 hours ago [-]
They announced a partnership with Microsoft today.
The niche is so big that Microsoft invented WSL to run Linux programs on Windows.
pjmlp 14 hours ago [-]
And Julia as well.
rirze 9 hours ago [-]
It's a sad time to be a fan of Julia-- everyone forgets it's there.
archargelod 7 hours ago [-]
I was excited to try Julia, but then, as I saw it was an interpreted language, with bulky runtime, slow startup times and bloated library sizes - my initial interest quickly faded.
For the same reasons I see languages like Python, Java, C# as inferior.
Archit3ch 2 hours ago [-]
Julia compiles to native code, same as C++/Rust.
pjmlp 5 hours ago [-]
Java and C# definitely don't belong on the same basket.
And inferior to what, the crab?
archargelod 2 hours ago [-]
Inferior to languages that compile to native binaries, not burning dramatically more cpu cycles than necessary.
pjmlp 2 hours ago [-]
Showing your ignorance regarding Java and C# ecosystems and available compilers on that reply.
archargelod 1 hours ago [-]
I indeed don't know about Java, but with C# there are a lot of limitations if you want AOT compilation and you still get the bloated binary and limited performance.
I also, personally, never seen a single project written in either Java or C# that distributes aot binaries.
pjmlp 5 hours ago [-]
Especially when it is actually successful at what it was designed to be, a faster Python for data science folks, having gotten enough researchers, more than most toy languages that almost daily drop on HN and Reddit.
totalperspectiv 18 hours ago [-]
This is really exciting. I've been using Mojo off and on for side projects over the last two years.
(copying from some previous Mojo threads) It's got an ownership system adjacent to Rust, comptime similar to Zig, and a first class dependent type system. Even more exciting, is that uses LLVM (to the best of my understanding) in some novel ways and for more optimizations.
dlahoda 16 hours ago [-]
Hm, in docs they say that dependent type system is not first class seems.
Is it even dependent? More like refinement types, which seems will be in Rust too.Also HN recently mentioned Rust building similar llvm based integration with GPU.
But compared with Python, Julia, Matlab, R, Rust, C, C++ - Mojo feel relief for working with numerics.
Archit3ch 1 hours ago [-]
> But compared with Python, Julia, Matlab, R, Rust, C, C++ - Mojo feel relief for working with numerics.
Out of those, Julia is the only one that combines Multiple Dispatch and native code, both important for numerics.
Technically soruce available now with the promise of accepting contributions (thus becoming fully open source) early next year. But since it is an Apache 2 license (like the rest of the LLVM project) you are already allowed to fork and contribute to your own fork right now, just no upstreaming.
For many the closed source nature of the compiler was a knock-out criterion. We will see if Mojo can gain traction now or if it has missed its window of opportunity.
cube2222 17 hours ago [-]
It’s open source under the Apache 2 license, not source available.
Accepting contributions is not required to be open source.
SQLite doesn’t accept contributions from random people either [0] (though you could argue being public domain isn’t being open source).
Anyway, this is great, I was waiting for this to take the language for a spin! Congrats to the Mojo team!
Maybe it is not listed by the OSI, but it is 'open source' in practice, if the source is also in the public domain. The FSF's definition of free software makes more sense not only ideologically, but also because it does not try to be exhaustive.
SwellJoe 15 hours ago [-]
You're just making up your own definitions of things.
If the complete source is available and distributable under an OSI-approved license, it is absolutely Open Source. Accepting outside contributions is nowhere in the definition of Open Source.
fluffybucktsnek 17 hours ago [-]
Technically, the criteria for open source is freedom to freely distribute and modify the source code, not to upstream changes. That's a different for thing.
https://www.joelonsoftware.com/2002/06/12/strategy-letter-v/
Any good resources for getting started? And anything on doing NumPy/SciPy-like stuff in it?
For the same reasons I see languages like Python, Java, C# as inferior.
And inferior to what, the crab?
I also, personally, never seen a single project written in either Java or C# that distributes aot binaries.
(copying from some previous Mojo threads) It's got an ownership system adjacent to Rust, comptime similar to Zig, and a first class dependent type system. Even more exciting, is that uses LLVM (to the best of my understanding) in some novel ways and for more optimizations.
Is it even dependent? More like refinement types, which seems will be in Rust too.Also HN recently mentioned Rust building similar llvm based integration with GPU.
But compared with Python, Julia, Matlab, R, Rust, C, C++ - Mojo feel relief for working with numerics.
Out of those, Julia is the only one that combines Multiple Dispatch and native code, both important for numerics.
Mojo 1.0
https://news.ycombinator.com/item?id=49261128
lol, feels like espionage
https://github.com/modular/modular/blob/main/KGEN/docs/Desig...
Compiler walkthrough
https://github.com/modular/modular/blob/main/KGEN/docs/MojoC...
For many the closed source nature of the compiler was a knock-out criterion. We will see if Mojo can gain traction now or if it has missed its window of opportunity.
Accepting contributions is not required to be open source.
SQLite doesn’t accept contributions from random people either [0] (though you could argue being public domain isn’t being open source).
Anyway, this is great, I was waiting for this to take the language for a spin! Congrats to the Mojo team!
[0]: https://simonwillison.net/2025/Dec/29/copyright-release/
If the complete source is available and distributable under an OSI-approved license, it is absolutely Open Source. Accepting outside contributions is nowhere in the definition of Open Source.
https://opensource.org/osd