trivia VS gcc

I've used it. :)

https://github.com/guicho271828/trivia/issues/108

You can see it, for instance, in the Trivia library ( https://github.com/guicho271828/trivia/blob/master/level0/impl.lisp ): the macro match0 is a thin wrapper around the function parse-patterns, and this, in turn, calls the function make-pattern-predicate which performs the recursive destructuring of patterns.

I can agree it's not the same, but what's the point? A more interesting disagreement is that I wouldn't say it's a downside (though yes, there are tradeoffs). Especially in Current Year when open source is fashionable and pretty much every language has a package manager to make pulling in or swapping out dependencies pretty easy, I don't see the issue. It's also interesting to note that of all the things Clojure did to "fix" shortcomings of past languages with a more opinionated (and often more correct I'll admit) design philosophy that users are forced to use (even when it's not more correct), infix-math-out-of-the-box wasn't one of them. I don't think that specifically really hurt Clojure adoption. (But of course Clojure is reasonably extensible too so it also has a macro package to get the functionality, though it's more fragile especially around needing spaces because it's not done with reader macros.)

I've brought the library up many times because CL, unlike so many other languages, really lets you extend it. Want a static type system? https://github.com/coalton-lang/coalton/ Want pattern matching? No need to wait for PEP 636, https://github.com/guicho271828/trivia/ If all that keeps someone from trying CL, or from enjoying it as much as they could because of some frustration or another, due to lacking out of the box, chances are it is available through a library.

Great libraries like trivia, iterate/for/alternative loop libraries, alexandria, and a hundred others. Common Lisp is a general purpose programming language with good support for ffi, working with files, databases, images, audio, etc. Just skim awesome-cl if you haven't. You could argue this doesn't have to do with the language, but a lot of these libraries are so good (or even possible) in part because of language features elisp does not have.

> After much deliberation, the Python Steering Council is happy to announce that we have chosen to accept PEP 634, and its companion PEPs 635 and 636, collectively known as the Pattern Matching PEPs

This is why I'm still enamored with Lisp. One doesn't wait around for the high priests to descent from their lofty towers of much deep pontification and debate with shiny, gold tablets inscribed with how the PEPs may be, on behalf of the plebes. One just adds new language feature themselves, eg. pattern matching[1] and software transactional memory[2].

1. https://github.com/guicho271828/trivia

2. https://github.com/cosmos72/stmx

The source is impressively simple! Good job!

I have been implementing a pattern matcher for scheme based on the Balland pattern optimized, and every time I see pattern matchers for python I always get the feeling that the code you are replacing have to be truly awful for the rather contrived pattern matching syntax to be a net win. Compare any of the python pattern matchers to something like trivia in Common Lisp [0] and you see what I mean.

How do people use the python pattern matchers? I am genuinely curious. One benefit that I see is that you can build patterns at run-time which could be useful.

[0]: https://github.com/guicho271828/trivia/wiki/Type-Based-Destr...

As far as I know, libstdc++'s representation has two advantages:

First, it simplifies the implementation of `s.data()`, because you hold a pointer that invariably points to the first character of the data. The pointer-less version needs to do a branch there. Compare libstdc++ [1] to libc++ [2].

[1]: https://github.com/gcc-mirror/gcc/blob/065dddc/libstdc++-v3/...

[2]: https://github.com/llvm/llvm-project/blob/1a96179/libcxx/inc...

Basically libstdc++ is paying an extra 8 bytes of storage, and losing trivial relocatability, in exchange for one fewer branch every time you access the string's characters. I imagine that the performance impact of that extra branch is tiny, and massively confounded in practice by unrelated factors that are clearly on libc++'s side (e.g. libc++'s SSO buffer is 7 bytes bigger, despite libc++'s string object itself being smaller). But it's there.

The second advantage is that libstdc++ already did it that way, and to change it would be an ABI break; so now they're stuck with it. I mean, obviously that's not an "advantage" in the intuitive sense; but it's functionally equivalent to an advantage, in that it's a very strong technical answer to the question "Why doesn't libstdc++ just switch to doing it libc++'s way?"

Upd: searching in the github mirror by the commit hash from the issue, found that https://github.com/gcc-mirror/gcc/commit/1e3312a25a7b34d6e3f... is in fact in the 'releases/gcc-14.1.0' tag.

Even weirder that this one got swept under the changelog rug, it's a pretty major issue.

> It's true, this was a CVE in Rust and not a CVE in C++, but only because C++ doesn't regard the issue as a problem at all. The problem definitely exists in C++, but it's not acknowledged as a problem, let alone fixed.

Can you find a link that substantiates your claim? You're throwing out some heavy accusations here that don't seem to match reality at all.

Case in point, this was fixed in both major C++ libraries:

https://github.com/gcc-mirror/gcc/commit/ebf6175464768983a2d...

https://github.com/llvm/llvm-project/commit/4f67a909902d8ab9...

So what C++ community refused to regard this as an issue and refused to fix it? Where is your supporting evidence for your claims?

Somewhat related: In 2020 gcc bumped the requirement for bootstrapping to be a C++11 compiler [0]. Would have been fun to see the kernel finally adopt C++14 as the author suggested.

I don't think that Linus will allow this since he just commented that he will allow rust in drivers and major subsystems [1].

I do found it pretty funny that even Linus is also not writing any rust code, but is reading rust code.

I would have hoped see more answers or see something in here from actual kernel developers.

0: https://github.com/gcc-mirror/gcc/commit/5329b59a2e13dabbe20...

> They’re saying that a lot of the restrictions makes things much harder than other languages. Hence the general problem rust has where a lot of trivial tasks in other languages are extremely challenging.

Like what? So far the discussion has revolved around rewriting a linked list, which people generally shouldn't ever need to do because it's included in the standard lib for most languages. And it's a decidedly nontrivial task to do as well as the standard lib when you don't sacrifice runtime overhead to be able to handwave object lifecycle management.

- C++: https://github.com/gcc-mirror/gcc/blob/master/libstdc%2B%2B-...

- Rust: https://doc.rust-lang.org/beta/src/alloc/collections/linked_...

> No need to get defensive, no one is arguing that rust doesn’t do a lot of things well.

That's literally what bsaul is arguing in another comment. :)

> You’re talking up getting a safe implementation in C, but what matters is “can I get the same level of safety with less complexity in any language”, and the answer is yes: Java and c# implementations of a thread safe linked list are trivial.

Less perceived complexity. In Java and C# you're delegating the responsibility of lifecycle management to garbage collectors. For small to medium scale web apps, the added complexity will be under the hood and you won't have to worry about it. For extreme use cases, the behavior and overhead of the garbage collector does became relevant.

If you factor in the code for the garbage collector that Java and C# depend on, the code complexity will tilt dramatically in favor of C++ or Rust.

However, it's going to be non-idiomatic to rewrite a garbage collector in Java or C# like it is to rewrite a linked list in Rust. If we consider the languages as they're actually used, rather than an academic scenario which mostly crops up when people expect the language to behave like C or Java, the comparison is a lot more favorable than you're framing it as.

> If I wanted I could do it in c++ though the complexity would be more than c# and Java it would be easier than rust.

You can certainly write a thread-safe linked list in C++, but then the enforcement of any assumptions you made about using it will be a manual burden on the user. This isn't just a design problem you can solve with more code - C++ is incapable of expressing the same restrictions as Rust, because doing so would break compatibility with C++ code and the language constructs needed to do so don't exist.

So it's somewhat apples and oranges here. Yes, you may have provided your team with a linked list, but it will either

GCC is also written in C++, and has had C++ deps since 2013:

https://github.com/gcc-mirror/gcc/blob/master/gcc/c/c-parser...

Compliers/Interpreters are also very commonly open source (here is the source code for a popular C compiler). That means you can even modify the compiler's code and change its behavior if you wanted to.