librope
ATS-Postiats
librope | ATS-Postiats | |
---|---|---|
4 | 18 | |
265 | 349 | |
- | - | |
0.0 | 0.0 | |
over 2 years ago | over 1 year ago | |
C | ATS | |
GNU General Public License v3.0 or later | GNU General Public License v3.0 or later |
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
librope
- Show HN
-
The case against an alternative to C
Yep. A few years ago I implemented a skip list based rope library in C[1], and after learning rust I eventually ported it over[2].
The rust implementation was much less code than the C version. It generated a bigger assembly but it ran 20% faster or so. (I don't know why it ran faster than the C version - this was before the noalias analysis was turned on in the compiler).
Its now about 3x faster than C, thanks to some use of clever layered data structures. I could implement those optimizations in C, but I find rust easier to work with.
C has advantages, but performance is a bad reason to choose C over rust. In my experience, the runtime bounds checks it adds are remarkably cheap from a performance perspective. And its more than offset by the extra optimizations the rust compiler can do thanks to the extra knowledge the compiler has about your program. If my experience is anything to go by, naively porting C programs to rust would result in faster code a lot of the time.
And I find it easier to optimize rust code compared to C code, thanks to generics and the (excellent) crates ecosystem. If I was optimizing for runtime speed, I'd pick rust over C every time.
[1] https://github.com/josephg/librope
[2] https://github.com/josephg/jumprope-rs
-
Why Is C Faster Than Java (2009)
> itβs not clear if this will be a positive for native dev advocacy
I've rewritten a few things in rust. Seems pretty positive to me, because you can mix some of the best optimizations and data structures you'd write in C, with much better developer ergonomics.
A few years ago I wrote a rope library in C. This is a library for making very fast, arbitrary insert & delete operations in a large string. My C code was about as fast as I could make it at the time. But recently, I took a stab at porting it to Rust to see if I could improve things. Long story short, the rust version is another ~3x faster than the C version.
https://crates.io/crates/jumprope
(Vs in C: https://github.com/josephg/librope )
The competition absolutely isn't fair. In rust, I managed to add another optimization that doesn't exist in the C code. I could add it in C, but it would have been really awkward to weave in. Possible, but awkward in an already very complex bit of C. In rust it was much easier because of the language's ergonomics. In C I'm using lots of complex memory management and I don't want to add complexity in case I add memory corruption bugs. In rust, well, the optimization was entirely safe code.
And as for other languages - I challenge anyone to even approach this level of performance in a non-native language. I'm processing ~30M edit operations per second.
But these sort of performance results probably won't scale for a broader group of programmers. I've seen rust code run slower than equivalent javascript code because the programmers, used to having a GC, just Box<>'ed everything. And all the heap allocations killed performance. If you naively port python line-by-line to rust, you can't expect to magically get 100x the performance.
Its like, if you give a top of the line Porsche to an expert driver, they can absolutely drive faster. But I'm not an expert driver, so I'll probably crash the darn thing. I'd take a simple toyota or something any day. I feel like rust is the porsche, and python is the toyota.
-
Rust is now overall faster than C in benchmarks
> I have no idea whether that matters or even easy to measure...
It is reasonably easy to measure, and the GP is about right. I've measured a crossover point of around a few hundred items too. (Though I'm sure it'll vary depending on use case and whatnot.)
I made a rope data structure a few years ago in C. Its a fancy string data structure which supports inserts and deletes of characters at arbitrary offsets. (Designed for text editors). The implementation uses a skip list (which performs similarly to a b-tree). At every node we store an array of characters. To insert or delete, we traverse the structure to find the node at the requested offset, then (usually) memmove a bunch of characters at that node.
Q: How large should that per-node array be? A small number would put more burden on the skip list structure and the allocator, and incur more cache misses. A large number will be linearly slower because of all the time spent in memmove.
Benchmarking shows the ideal number is in the ballpark of 100-200, depending on CPU and some specifics of the benchmark itself. Cache misses are extremely expensive. Storing only a single character at each node (like the SGI C++ rope structure does) makes it run several times slower. (!!)
Code: https://github.com/josephg/librope
This is the constant to change if you want to experiment yourself:
https://github.com/josephg/librope/blob/81e1938e45561b0856d4...
In my opinion, hash tables, btrees and the like in the standard library should probably swap to flat lists internally when the number of items in the collection is small. I'm surprised more libraries don't do that.
ATS-Postiats
- What is the most feature-rich programming language
- Evolutie limbaje in industrie
-
The Little Typer β The Beauty of Dependent Type Systems, One Step at a Time
This is one of my two favorite books in The Little ...er series. The other is The Rational Schemer. These are two of the most advanced books in the series.
The Little Typer provides an introduction to dependent types. These can by used to guarantee things like "applying 'concat' to a list of length X and list of length Y returns a list of X+Y". It is also possible, to some extent, to use dependent types to replace proof tools like Coq. Two interesting languages using dependent types are:
- Idris. This is basically "strict Haskell plus dependent types": https://www.idris-lang.org/)
- ATS. This is a complex systems-level language with dependent types: http://www.ats-lang.org/
The Rational Schemer shows how to build a Prolog-like logic language as a Scheme library. This is a very good introduction to logic programming and the implementation of backtracking and unification is fascinating.
This is an excellent series overall, but these two books are especially good for people who are interested in unusual programming language designs. I don't expect dependent types or logic programming to become widely-used in the next couple generations of mainstream languages, but they're still fascinating.
-
Does Rust have any design mistakes?
Not being ATS
-
The case against an alternative to C
> any safety checks put into the competing language will have a runtime cost, which often is unacceptable
This is completely wrong. The best counterexample is probably ATS http://www.ats-lang.org which is compatible with C, yet also features dependent types (allowing us to prove arbitrary statements about our programs, and check them at compile time) and linear type (allowing us to precisely track resource usage; similar to Rust)
A good example is http://ats-lang.sourceforge.net/DOCUMENT/ATS2CAIRO/HTML/c36.... which uses the Cairo graphics library, and ends with the following:
> It may seem that using cairo functions in ATS is nearly identical to using them in C (modulo syntatical difference). However, what happens at the level of typechecking in ATS is far more sophisticated than in C. In particular, linear types are assigned to cairo objects (such as contexts, surfaces, patterns, font faces, etc.) in ATS to allow them to be tracked statically, that is, at compile-time, preventing potential mismanagement of such objects. For instance, if the following line:
val () = cairo_surface_destroy (sf) // a type error if omitted
-
Security advisory: malicious crate rustdecimal | Rust Blog
For a low level language in which you actually need to prove that your code doesn't cause UB, see http://www.ats-lang.org/
-
Why is ATS not considered in the design of modern system languages?
Here's the homepage fo the language: http://www.ats-lang.org/. The trick to finding results about with google is to search "ATS programming language".
-
ESPOL, NEWP, Mesa, Cedar, Modula-2, Modula-2+, Modula-3, Oberon, Oberon-2, Component Pascal, Active Oberon, D, C#, F#, VB, Ada, Go, Swift, just a few examples.
In SPARK's case, you have to state your invariants in even greater precision than in Rust, and naturally it has worse inference. That's okay, the same happens in a certain language with Atrocious Type Syntax.
-
What are all the situations you can't do compile time type-checking when building a programming language?
Yes, things like mentioned in the post can be expressed and checked statically, as demonstrated by languages like Idris and ATS. ATS might be even more relevant as it's an imperative language too, it can get rather low-level (like talking about properties of C runtime functions) while proving required properties statically, and it includes a solver for certain amount of arithmetics so that you don't need to prove obvious mathematical identities to the compiler. http://www.ats-lang.org/
- Is it possible to make a functional programming language that is equivalent of Rust in terms of performance and resource efficiency?
What are some alternatives?
c2rust - Migrate C code to Rust
lean4 - Lean 4 programming language and theorem prover
mu - Soul of a tiny new machine. More thorough tests β More comprehensible and rewrite-friendly software β More resilient society.
chapel - a Productive Parallel Programming Language
c3c - Compiler for the C3 language
cicada - An old-school bash-like Unix shell written in Rust
proposal-explicit-resource-management - ECMAScript Explicit Resource Management
jumprope-rs
virgil - A fast and lightweight native programming language
buffet - All-inclusive Buffer for C
HVM - A massively parallel, optimal functional runtime in Rust