I think Nim is an impressive language that does a lot of things really well. I don't think the memory management is one of them. I believe that memory management and compilation to C are the only two major things I've ever talked about in regards to Nim, because I'm abstractly interested in those topics. If an article about thread-local deferred reference counting in Ruby hit the top of HN and the comments were talking about how that's good for games, I'd probably comment there too.
And how do you do "memory management well"? Like Rust? You pay a high price in complexity and inflexibility for that juicy GC-less yet safe memory management.
Ref counting is not superior or inferior to explicit, restrictive ownership semantics. Those are simply different trade-offs.
Nim might be strictly inferior for writing a heavily multi-threaded web browser because of its memory management approach but that does not mean the approach is generally inferior.
Seems to me that Nim aims to be a "casual", rapid development / friendly (Python-like) language. Ownership semantics like in Rust do not fit there.
I'm personally a fan of regular old Java/C#-like concurrent garbage collection for most "scripting" languages (perhaps surprisingly, given my work on Rust). It's a lot of work to get there, but I think there's no substitute for doing the work—apps really end up needing the flexibility of shared memory. Shortcuts that seem simple like DRC end up tending to run into walls in practice, which is something that the other languages discovered—history keeps pointing to the HotSpot-style garbage collector as the one that systems that need to offer a simple, general-purpose garbage-collected programming model migrate to.
For different use cases Rust-style ownership semantics (when the performance of GC and runtime interoperability become an issue), or Azul-style pauseless GC (when you're willing to trade throughput for latency), or shared-nothing architectures (when you need them for legacy reasons like JavaScript, or want a simple programming model like Erlang) can work great.
I'm guessing because Nim gets portrayed as safe, or offers some safe features, but overall is not memory safe. Rust has worked very hard and gotten through the problem of having memory safety, with zero runtime cost and reasonably good language features.
Since it's 2015, it seems fair to point out when a new language offers something neat, but in a way that isn't safe.
Nim is as safe as any other language. Perhaps it's not as safe as Rust but that brings specific trade offs most people dont wan't to deal with. I don't understand why people think that Nim is "terribly unsafe" when in reality it's like any other language
With regards to memory safety, it is not. https://news.ycombinator.com/item?id=9050999 is an old comment from Patrick, but in today's Nim, it segfaults in both release and development modes for me. Rust's guaranteed memory safety means that Rust code (without explicit unsafe, the vast vast majority of code) cannot segfault.
> I don't understand why people think that Nim is "terribly unsafe" when in reality it's like any other language
For example, unless I write a bad cext, I cannot get Ruby to segfault.
None of this makes Nim a bad language. All languages have tradeoffs.
Yes Rust is more safe than Nim, I'm not arguing that. I'm also not arguing that Nim is as safe as languages with automatic memory management.
EDIT: Also, Nim is planning on turning those segfaults into runtime NilErrors and a nilChecks flag that will check for them at compile time, you can also avoid this by annotating Pointers with `not nil`
I probably should have been more clear, but I think it's safe to say that unlike C/C++, Nim can handle these types of issues like other languages that deal with pointers (Java, Go etc) with control from the programmer. The only memory safe language I know is Rust, but I am probably wrong on that part, so that's why I singled out Rust on how It's safer than Nim.
It has a feel of a scripting language, but as far as I can tell, it rather has the safety of C/C++, which I personally wouldn't call "safe like any other language".
Why not? I'm interested to know because in my opinion I don't see it any less safe than languages that don't have automatic memory management and/or languages like Rust.
Because it is flatly untrue? Memory safety is rather a binary thing. C# without /unsafe is safe. Same for Java and Rust. Not true for Nim or C/C++. Rust is unique in doing this without any GC or other runtime overhead, AFAIK, which makes it a bit special.
Nim does not have a separate unsafe keyword, because all unsafe features are already characterized by keywords; that's a result of its Pascal heritage. To check whether a piece of Nim code is safe, you check for the presence or absence of these keywords; e.g., you can grep for "ptr" in Nim, while grepping for "*" in C# isn't particularly helpful. Every unsafe feature in Nim has an associated keyword/pragma. Having a special "unsafe" keyword that says, essentially, "this procedure can contain other unsafe keywords" is sort of superfluous.
Note: these unsafe features have two purposes. One is to interface with C/C++ code. The other is to be able to write close-to-the-metal code in Nim rather than in C (where you wouldn't gain any safety by using C, but lose the expressiveness of Nim). This is, for example, how Nim's GC is itself written in Nim.
None of the unsafe features are necessary for high-level programming, i.e. unless you actually want to operate that close to the metal.
when --nilChecks:On become a thing, dereferencing null pointers will be like Java, a NilError (NullPointerException in Java). This is why I said it's as safe mainstream languages that dont have AMM but languages like Rust are safer than those mainstream languages. any others to point out?
You yourself know that this claim is entirely unsubstantiated, as evidenced by the fact that you felt the need to create a throwaway account. pcwalton is an active commentator throughout HN in general, and garbage collection and parallelism are two of his areas of expertise. If his opinion is somehow uninformed, then tell him so and explain how. If he's not uninformed, then the only thing your comment is doing is trying to shut down legitimate criticism.
All languages have faults. Engage with your critics, own your faults, and either correct them or justify them based on your principles.
EDIT: To give an example, pcwalton also initially criticized Go for not being memory-safe for values of GOMAXPROCS greater than 1. However, the Go team later implemented the dynamic race detector, which, if you've followed pcwalton's comments at all, you know that he is actually quite impressed with.
I always post using throwaways since I don't like karma influencing the content of my posts and it also makes it significantly more difficult for third parties to profile me.
This is some glass-houses logic right here, given that you're attempting to leverage trivially-falsifiable assertions in order to profile pcwalton as a Nim hater with a personal vendetta. In the meantime you have yet to actually address his criticisms, which, to reiterate, indicates that you're trying to shut down critics via deflection.
(I suppose, in the future, pcwalton should just generate a throwaway before commenting on Nim.)