Whilst the Julia version currently beats Mojo, I fully expect both to approach basically the same performance with enough tinkering, and for that performance to be on par with C or Fortran.

A more interesting question is which version is more elegant, ‘obvious’ and maintainable. (Deeply familiar with both, but money is on Julia).

An even more interesting question is: which version will actually entice millions of independed and variably motivated actors from all walks of life to commit and invest to a particular ecosystem. Technnical and usability aspects play only a minor role in technology adoption. In particular the best technology doesnt always win.

My humble two pennies is that Julia is missing the influencer factor: being endorsed by widely known entities that will attract the attention of both corporate eyes and the hordes of developers constantly looking for the next big thing.

Your money might be on Julia but $100mln was just placed on the Mojo/Modular bet...

I've tried julia a handful of times. IMO, the thing slowing adoption is that the usecases where julia feels like the most powerful, optimal choice are too limited. For example

- Slow startup times (e.g., time-to-first-plot) kill it's a appeal for scripting. For a long time, one got told that the "correct" way to use julia was in a notebook. Outside of that, nobody wanted to hear your complaints.

- Garbage collection kills it's appeal for realtime applications.

- The potential for new code paths to trigger JIT compilation presents similar issues for domains that care about latency. Yes, I know there is supposedly static compilation for julia, but as you can read in other comments here, that's still a half baked, brittle feature.

The second two points mean I still have the same two language problem I had with c++ and python. I'm still going to write my robotics algorithms in c++, so julia just becomes a glue language; but there's nothing that makes it more compelling that python for that use. This is especially true when you consider the sub-par tooling. For example, the lsp is written julia itself, so it suffers the same usability problems as TTFP : you won't start getting autocompletions for several minutes after opening a file. It is also insanely memory hungry to the extent that it's basically unusable on a laptop with 8gb of ram (on the other hand, I have no problem with clangd). Similarly, auto-formatting a 40 line file takes 5 seconds. The debugging and stacktrace story is similarly frustrating.

When you take all of this together, julia just doesn't seem worth it outside of very specific uses, e.g., long running large scale simulations where startup time is amortized away and aggregate throughput is more important than P99 latency.

On garbage collection and real-time applications, there is this [2] talk where ASML (the manufacturer of photolithography machines for TSMC) uses Julia for it. Basically it preallocates all memory needed before hand and turns off the garbage collector.

On the same more about real-time, if your call stack is all type stable [3], the you can be sure that after the first call (and subsequent compilation), the JAOT compiler won't be triggered.

About static compilation, there are two different approaches * PackageCompiler.jl [4], which is rally stable and used in production today. It has he downside of generating huge executables, but you can do work to trim them. There is still work to do on the size of them. * StaticCompiler.jl [5], which is still in the experimental phase. But it is far from being completely brittle. It does puts several restrictions on the chide you can write and compile with it, basically turning Julia in a static type language. But it had been successfully used to compile linkable libraries and executables.

Some of the concerns you have about usability in your third paragraph have been worked on with the 1.9 and 1.10 (coming) releases. The LSP usage is better thanks to native code caching, maybe you can try it again (of you have time). The debugging experience I honestly think is top notch if you're using Debugger.jl+Revise.jl [6] [7], still I know there are some caveats in it. About stack traces, there is also a more of work done to make them better and more readable, you can read the with done in these PR's [8] [9] [10] [11, for state of Julia talk].

Still, I can understand that Julia might not be able (yet) to cover all the usecases or workflows of different people.

[1]: https://julialang.org/blog/2023/04/julia-1.9-highlights/#cac... [2]: https://www.youtube.com/watch?v=EafTuyy7apY [3]: https://docs.julialang.org/en/v1/manual/performance-tips/#Wr... [4]: https://julialang.github.io/PackageCompiler.jl [5]: https://github.com/tshort/StaticCompiler.jl [6]: https://github.com/JuliaDebug/Debugger.jl [7]: https://timholy.github.io/Revise.jl/stable/ [8]: https://github.com/JuliaLang/julia/pull/49117 [9]: https://github.com/JuliaLang/julia/pull/49959 [10]: https://github.com/JuliaLang/julia/pull/45069 [11]: https://www.youtube.com/watch?v=2D8oRtDJEeg&t=2487