one of the fastest shells out there will probably get even faster. ever since I switched from zsh to fish, my terminal productivity has gone up a lot.
from the link :
We have no real idea what the performance of the finished port is going to be. Early results are encouraging, but it is entirely possible this will be ~20% slower in some cases.> Fish also uses threads, for things like the autosuggestion and syntax highlighting, and we would like to have more "threads"/"concurrency"/"run-thing-in-backgroundness" (please insert the correct term here, I have never been good at these things). One large project has been to run multiple fish builtins and functions "at the same time", to enable things like backgrounding functions (ideally without using "subshells" because those are an annoying environment boundary that shows up in surprising places in other shells), and to simply be able to pipe two builtins into each other and have them actually process both ends of the pipe "simultaneously".
> C++ offers few guarantees on what can be accessed from which thread. @ridiculousfish has been trying to crack this for years, and hasn't been confident enough in his solution. We want a tech stack that helps us here, and C++ doesn't.
The initial rewrite may be no faster, or possibly slower as stated, but long-term they'd be able to safely add more concurrency or parallelism that they weren't able to before.
It is easier to make correct program faster than making a fast program correct!Yes, Rust's BC is a great technology, but C++ is not a runaway nuclear fire which contaminates and melts everything around it when it comes to sanity and security.
Yes, Rust allows you to run amok by not allowing it, but you can design a good foundation to your code which prevents tons of problems out of the gate in C++, and this is without using smart-pointers and other things available to you.
And there is an almost perfect overlap between the people capable of pulling off a rewrite like this and the people who would write a good C++ foundation in the first place.
I never meant to imply such a thing. However, Rust is simply a much better-defined language. Moves do what you expect, smart pointers work like you'd expect, there are not 3 (or 5) different types of constructors you have to understand and implement properly if you want to build your own abstractions. You don't have to remember where to put std::move, you don't have to remember what happens to the variable after you move out of it, you don't have to use the awful variant accessor functions if you want a tagged union and so on.
Yes, you can do all this in C++. You can build safe abstractions. You can build layers on top of the STL to make it less awful. You can make use of modules and #embed and other nice new features that C++ is getting. But you need to be a lot more careful compared to Rust, because the compiler is not going to help you.
Not sanity, maybe. But security? How much more would it take to declare a nuclear meltdown: https://alexgaynor.net/2020/may/27/science-on-memory-unsafet...
> doing anything the compiler can’t trivially optimize
What does compiler optimization have to do with libraries?
> single threaded
Plenty of C and C++ programs are multi threading using a system api like pthreads.
Agreed- do you have any to back up your original claim?
> > doing anything the compiler can’t trivially optimize
> What does compiler optimization have to do with libraries?
One of the most common reasons to use a library is because it has optimizations you want to use. For example, performance-sensitive programs link against OpenSSL even if they’re just using a couple of hash functions because the SHA-256 function you copied into your codebase won’t have their assembly backend or use of processor intrinsics. Repeat for string searches, pattern matching, all kinds of math, etc. where people have written libraries with pricessor-specific assembly, SIMD intrinsics, etc.
> Plenty of C and C++ programs are multi threading using a system api like pthreads.
Yes - and the long history of bugs related to that is why many stayed single-threaded because it was more work than the author had time for to make the code thread-safe. Rust’s “fearless concurrency” talk isn’t just marketing but a reaction by people with a lot of experience in the area realizing just how much more they used concurrency when it was easy to do correctly rather than infamously hard.
Linux, Maya, Photoshop, Chrome
> OpenSSL
When C programmers do crypto they also use OpenSSL, but more for security than performance. Do you have an example of a rust library which is a better substitute for commonly hand written C?
> fearless concurrency
Not related to the topic of discussion about performance gains of using libraries.
Consider the now-classic "Fearless Concurrency" post about Stylo: https://blog.rust-lang.org/2017/11/14/Fearless-Concurrency-I...
Strictly, C++ pretty much has to be no slower than Rust. But it's certainly possible that a regular human might in practice write higher-performing parallel code when using Rust.
Of course, you can't assume the absence of bugs in real world software. The C++ version would lack any of the safety added by Rust's compile time checks.
I will always take faster code, but that seems like an odd bulletpoint to highlight given the many quality of life improvements fish has to offer.
Those little delays add friction. Not an intolerable amount, sure, but it’s there. While I switched to fish for other reasons, that alone would keep me from going back now.
The nvm init was the worst of it, so now I have an alias for `$NVM_DIR/nvm.sh ] && \. "$NVM_DIR/nvm.sh" && \. $NVM_DIR/bash_completion` I just run manually before using nvm, rather than letting it slow me down half a second or whatever it was every time I open a new terminal.
It's worth poking around if things get slow enough to be a pain. There's a decent chance it's 1-2 things that you don't even care about all that much.
Its an asdf[2] rewrite, in rust, that can do most of the things nvm can
> --profile-startup=PROFILE_FILE > Will write timing for fish startup to specified file.
A lot or most of that wasn't zsh being slow though, but oh-my-zsh calling out to external programs (like git to get powerline info and such) and them being slow.
And that's 40 C processes. "python empty.py" takes about 30ms to 40ms due to the interpreter startup time; empty C file is about 2ms, "sh empty.sh" is about 4ms.
Please think that "launching external programs is fast and modern computers are fast, so why worry about this?", and that's true, but it's also not. Add up a few dozen and turns out it's actually quite slow.
As far as I'm aware, most of the other quality of life improvements can be reproduced in zsh with plugins. This performance bulletpoint makes me want to consider switching back to fish from zsh.
Surely you’re not typing and managing jobs at a pace where C vs C++ vs Rust vs $lang matters… or I’m missing something about what fish is bringing to the table.