Facebook is using D in production starting today
forum.dlang.org
forum.dlang.org
https://groups.google.com/forum/#!topic/golang-nuts/8k59RgkeJ6s
EDIT: Removed dot at the end of the URL
However, like many flaws with HN's underdeveloped software, you can't actually do that on HN because the parser includes the trailing > in the URL. So your best bet here is with whitespace.
<http://www.example.com>
"D has resolutely exited C++'s shade because it is good at things C++ is not good at, in addition to being good at things C++ is good at. Also, Go would be tenuous to frame as a better C because it cannot do everything C does - e.g. unsafe memory access and manual memory management, which are needed in certain systems - and it interoperates poorly with C."
In short, he states that D can do unsafe memory access and manual memory management. Go can't.
Go is a great systems programming language especially for modern concurrent systems — http servers etc. It talks to C easily so you can integrate all kinds of system level code into your apps. Having a Garbage collector makes it trivial to write long-running daemons.
Modern operating systems have traditionally been written in C (and C++) plus some assembly language code. D can do everything C & C++ can do but it would still no doubt need the assembly language code.
Go lacks manual memory management. Some say that this would be a barrier for writing an operating system while others don't. The fact that you would have to use some assembly language code to talk to the hardware and you might need to add some manual memory management via assembly language code. After that I'm sure the garbage collector would make the OS more reliable and potentially a little quicker in places.
Either way I don't see why Go gets criticised for needing a bootstrap layer when operating systems written in C and C++ also need this.
Systems programming doesn't seem to be a very well defined term. My understanding is that it is certainly not application programming and it requires pretty tight management of hardware resources. That includes things like operating systems, database systems, embedded systems, networking software like firewalls, etc.
[0] You know what I mean.
A GC is just a special case of a memory manager.
systems language => for building systems, many parts, many interconnections
operating system language => ability to use the hardware with no limitation. even for a monolithic part.
So... every language?
Actually, contrary to C and C++ language specification, in D, support for inline assembly is part of the language specification.
> downvote
sambeau 50 minutes ago | link | parent | flag
I fear you are confusing systems programming language and operating systems programming language (or conflating).
Go is a great systems programming language especially for modern concurrent systems — http servers etc. It talks to C easily so you can integrate all kinds of system level code into your apps. Having a Garbage collector makes it trivial to write long-running daemons.
Modern operating systems have traditionally been written in C (and C++) plus some assembly language code. D can do everything C & C++ can do but it would still no doubt need the assembly language code.
Go lacks manual memory management. Some say that this would be a barrier for writing an operating system while others don't. The fact that you would have to use some assembly language code to talk to the hardware and you might need to add some manual memory management via assembly language code. After that I'm sure the garbage collector would make the OS more reliable and potentially a little quicker in places.
While I am on the D and Rust field, I support Go's ability to do this.
Go is no different from Oberon in system capabilities. And Oberon was used to write quite a few desktop systems used at Zurich's ETHZ during the mid to late 90's.
The OS bootloader and the kernel package for hardware interactions were written in Assembly, with the remaing parts in Oberon.
You can read all about it here, http://www.inf.ethz.ch/personal/wirth/books/ProjectOberon.pd...
> Either way I don't see why Go gets criticised for needing a bootstrap layer when operating systems written in C and C++ also need this.
Because many tend to assume compiler extensions to C and C++ are part of the language.
It is a fun quiz asking C and C++ developers what is part of the standard and what is compiler specific behaviour.
What really bothers me about Go is not really that it's garbage collected, but rather that its garbage collector sucks so badly. Really, not all garbage collectors are created equal.
For example I'm working on a startup and we've been integrating with various bidding exchanges for serving targeted ads. All the bidding exchanges want the response to be generated in under 100ms, which includes the network roundtrip. This means on the server-side, the average must not be higher than 10ms per request, preferably lower. Scala on the JVM can handle it, but when I tried out Go, it was a disaster ... as that garbage collector stops the world and it's totally unpredictable, so you end up with spikes of latency that can upset your partners and given enough incoming requests, it can also blow up your buffers/queues, crashing your servers. It's also non-compacting, but that's a given, as it's not even fully precise yet.
Which is the reason for why integrations with bidding exchanges are usually written in C++ too (in case it's not clear, we are talking about B2B web services). We've gone with the JVM because it provides a good productivity/performance balance, but eternal vigilance is needed in profiling the memory allocation patterns and tuning the garbage collector to handle the load. And Go requires even more tuning. Which is why sometimes I fantasise about a high-level language that allows for manual memory management, as things would be so much easier ... although I'm rooting more for Mozilla's Rust, than I am for D.
What version of Go?
Message rate per second?
Message size?
What was the % increase over average response time during GC?
What class of hardware?
I did notice the Go's GC improved between 1.0 and 1.1.
Thanks!
In a lot of contexts, this is a feature (makes terrible code smells in normal code easier to see), but depending upon the type of coding you do, you do sometimes find yourself wishing it were a bit easier when dealing with things like graphics APIs where you just want to lock a texture, update some bits in-place, and then unlock it. Sometimes what might be a couple lines of C code are 10s of lines of Go code where you either do crazy gymnastics with the unsafe package, or juggle things in and out of byte buffers.
Others have been using it to distinguish languages suitable for writing operating systems/drivers years before Go introduced this confusion.
And does the unsafe package allow you to build a C-style manual allocator or not (regardless of whether it integrates with Go's new or make operators)?
http://dotsub.com/view/892ed71a-0d53-499d-aaa8-d5e642f2942c
Still, I think you raised valid question in the first part of your message, though the second is a bit offensive and I also thank Andrei for his clarification and use the opportunity to congratulate for this milestone of D language. I like D and even if I use C++ at work, I know I'd enjoy using D especially for the features that let my code "see" and "build" the other parts of the code.
It has literally transformed writing D code, and for the better. There's another little feature, -cov, which will tell you which lines of code are covered by the unit tests.
It's hard to understate the improvement these engender.
This changed with the recent 0.8, `for` is now syntax sugar for using the Iterator trait, which optimises exactly like C++ (the vector iterator even vectorises when LLVM can do it).
Rust has actually moved to have iterators that are very similar to (a subset of) D's ranges.
How does the language do this? Doesn't that have more to do with the design of the program itself? It certainly is a interesting security idea, much more strict than sending remote procedure calls or serializing objects and sending them across the network.
(Although due to this announcement, the site is being slammed at the moment. It's a single server hosting dlang.org, not a farm.)
I remember finding the website disturbingly fast on my first visit. I wonder if it is just me being so used to loading delays, or if there is a point were you can be so fast that it is detrimental to the user experience. The latter doesn't sound like it makes sense so it must be of matter of getting used to it.
Forums these days need to allow for multiple users to log in, read content and post messages. I'm pretty sure that the link above received several hundreds or thousands of users in a single hour. Forums these days also use database systems (or other services external to the process) that represent a big bottleneck. Then you've got the issue of static assets, like CSS, Javascripts, images and so on.
As a general rule of thumb, if you want scalability, you have to trade some throughput for it, as scalability concerns hurts performance.
That said, popular open-source web software, in general is awful in terms of everything.
It does not send a complex JSON object that is then marshalled into some kind of Angular-Knockout-Backbone framework of the day where complex magic creates views, links and templating language formats objects into HTML created via DOM.
As JS in the browser speed up, all those framework find some way of using it. Sure, your 5-item TODO list app looks good...
Back to the 90s URLs.
I mean, yes, superficially this is less obtuse:
http://advrider.com/forums/showthread.php?t=801516
But the number holds no meaning to a human either way.
http://advrider.com/forums/showthread.php?t=801515
exist (while http://advrider.com/forums/showthread.php?t=801517 doesn't at this time).
"Normally" such an app (avrider) would be set up with routing such that the url became /forum/thread/<id> -- and with a simple 6-digit id, that's much more managable to type/communicate manually than an uuid or something.
All that said, I basically agree -- exposing some "magic" constant/serial number to the user usually doesn't do much to help with the ux. It's actually an interesting problem: what would be the better, more "true" web/REST-like url-scheme for a forum? Perhaps forum/topic/sub-topic/thread-topic ? How limiting would that be wrt. reorganizing the forum threads (and not breaking links) -- this is especially an issue if there's a chance of re-using uri's -- it's annoying to have a link to one discussion morph into a link to another one. I don't think there are any solutions that are significantly better than a (symbolic/numerical) thread/topic id...
edit: Actually I see the sense in the email-id-like urls of the d-mars forum (or usenet-like).
It is ridiculously fast.
https://github.com/d-programming-language
Naturally, contributors are welcome!
If Google picked up D I would be much more interested as to why.
So, this is just one step forward, but it's a big one and exciting to the folks who are fans of D - especially those who have put a lot of time and effort into it.
The rest of Phobos is being looked at, but to this point I don't think it has been combed thoroughly enough to say "almost entire."
"Memory is usually managed with garbage collection, but specific objects can be finalized immediately when they go out of scope. Explicit memory management is possible using the overloaded operators new and delete, and by simply calling C's malloc and free directly. Garbage collection can be controlled: programmers can add and exclude memory ranges from being observed by the collector, can disable and enable the collector and force a generational or a full collection cycle. The manual gives many examples of how to implement different highly optimized memory management schemes for when garbage collection is inadequate in a program."
I wonder if the GC is stop-the-world.
> Stopping all other threads than the thread currently trying to allocate GC memory.
I checked, to get the facts straight: DMD is the reference implementation. The frontend is under GPL but the backend (optimizer and codegen) is not. The source code is available but you are not allowed to redistribute it.
https://github.com/D-Programming-Language/dmd/blob/master/sr...
(I wonder if you are allowed to fork it on GitHub.)
[1] http://gdcgnu.sourceforge.net/ [2] https://github.com/ldc-developers/ldc
(In my tests, they are also mostly the fastest ones, especially LDC ... see for example my comparisons in http://saml.rilspace.org/moar-languagez-gc-content-in-python... ... D with LDC is among the top contenders, together with various optimized C versions ...)
All this talk about D got me nostalgic about great group of people and a sense of accomplishment being made (with language and libraries) when I was using it. It makes me want to have another go, almost.
- C++11 is good enough (and a little better than that)
- The eco system. Yes, I can use C libs from dlang but managing extra bridges/headers is too much overhead if the alternative is just to throw them into my C++ project and use them without writing any glue code.
- The garbage collector. (RAII fan here)
- Tooling. Are there any good dlang IDEs with mature refactoring support and code completion?
For the tasks I'm using C++ for, C++11 is more than sufficient. For more abstract/high level stuff where I don't particularly care about top performance/memory layout I don't need another C++ contender but can use higher level languages/scripting languages.
D would look more tempting if there was no C++11 but for now for me I'm perfectly happy with C++.
Is it just that maintaining ownership semantics for heap memory tends to be more complicated than doing the same for file objects (much more rarely shared, I'd guess) or mutexes (not sure if "sharing" is even sensibly defined here).
In Rust, this style is enforced by the language. In C++11 you can enforce it by the convention of using std::unique_ptr and passing those between threads via a shared data structure like a blocking queue.
Also, you can use shared memory in Rust. If you do, the type system ensures there can be no data races: either the data is immutable or you must take the lock before you mutate the data.
It's not fundamentally different from having bound checks for array indices. You can either do that pretty easily at runtime or use a simple type system to do it at compile time (e.g., Boyapati's [1] or Flanagan's [2] work). It's been done, e.g. for Cyclone [3]. This is decades old stuff, not rocket science. Honestly, Monitors had the basic idea right in the 1970s, except as Per Brinch Hansen lamented [4], language designers keep screwing it up.
[1] http://www.pmg.lcs.mit.edu/~chandra/publications/oopsla02.pd...
[2] http://users.soe.ucsc.edu/~cormac/papers/esop99.pdf
[3] https://homes.cs.washington.edu/~djg/papers/cycthreads.pdf
- RAII-style freeing means a lot of reference counting. Reference counting and multiple threads don't mix well. You can circumvent that by having multiple separate heaps, but that's not always a practical solution.
- Reference counting is slow; if you want GC-like speed and RC-like pause time guarantees, you're probably better off with deferred reference counting, but that's not easy to engineer into C++; it's essentially a form of garbage collection.
- Lack of fully automatic memory management may affect modularity adversely; see Jones/Lins for the gory details. In brief, wholly or partly manual memory management creates leaky abstractions (this is if you eschew RC for some of your code/types for speed reasons or because you need to deal with cyclic references).
- It is not difficult to have scoped deallocation for resources (scope statement in D, using statement in C#, etc., destructor pragma in Nimrod). Resource lifetime, in any event, does not always coincide with the lifetime of a variable, so this is an incomplete solution. Using GC does not mean not using RAII where its downsides do not matter.
[1]http://www.hpl.hp.com/personal/Pramod_Joisha/Publications/is...
The attraction of RAII is that it's a pretty simple mechanism that doesn't require compiler intervention outside of basic, already existing optimizations such as inlining.
You can't say reference counting is bad for multi-threaded programs without mentioning that GC is also bad for multi-threaded programs, since the garbage collector has to pause all other threads, either for the entirety of the GC run or (if you're lucky and using a good GC) for parts of it.
The modularity argument is reasonable, and I've been annoyed by this aspect several times, though in the majority of cases it doesn't seem to be an issue.
The problem with reference counting in concurrent programs is one of correctness, not one of speed [1] because every change of a reference count is a potential race condition. That's quite different from the challenges garbage collection faces in a multi-threaded environment.
Whether a garbage collector has to pause all threads is an implementation issue. Modern garbage collectors can limit that pause effectively to the root scanning phase, then let the collector run concurrently with the mutator. You can also work around pausing threads entirely, though the tradeoffs are rarely worth it outside of hard realtime environments.
Note also that this is an issue of pause time, not performance. While HN can get obsessed with pause times, not everyone programs video games, embedded systems, or kernel drivers where that matters. High-performance computing, for example, is a huge field where pause times are all but irrelevant and where amortized cost is what matters. (HPC is also where correctness can become easily more important than squeezing out a percent or more of performance through low-level hacks; if a job that takes several days to run crashes halfway through, that's an enormous loss.)
[1] Technically, you can make reference count updates atomic, but the overhead is absurd, especially under contention. Hence why SNZIs [2] exist, which reduce the speed overhead at the expense of additional memory overhead. [2] http://dl.acm.org/citation.cfm?id=1281106
The (my) problem is that it also matters whenever a program holds lots of data in memory (databases, data analysis, caching, etc). As the cost of RAM decreases, the importance of this problem increases, i.e. fast.
Incremental garbage collection isn't a new technology [1] or one that's particularly difficult to implement by itself (a grad student could probably implement Baker's treadmill in a couple of days); what makes it hard is primarily compaction and multiple threads [1]. You can't effectively use (naive) RC with multiple threads and you don't get compaction with RC, either. Multi-threading is in practice a major driver for the need of GC, since (naive) RC isn't thread-safe and unpredictable object lifetimes don't go well with manual memory management.
Also, deferred RC strategies can under certain circumstances contain the cost for cycle collection. Trial deletion is already limited to nodes reachable from other nodes whose reference count has been decremented; type information can be leveraged further to exclude nodes that cannot possibly be parts of cycles (this is particularly easy in ML-style languages, which make mutually recursive types explicit in the source code, but is not limited to those [2]).
Finally, you can also use multiple disjoint heaps to simplify implementation and cap GC cost (one per thread and zero or more shared heaps). This can also bring naive RC back into play as a viable strategy, though you'd still lose compaction. Multiple heaps are particularly attractive for NUMA architectures.
[1] I note that hard realtime guarantees are difficult to make with a basic incremental collector due to the potential of pathological behavior, but we are not talking about hard realtime guarantees here.
[2] Obviously, JITs and dynamically or weakly typed languages have a harder time with this approach.
Not necessarily, but in practice they do go hand in hand. I didn't say the problem was impossible to solve, just that it is an important problem that needs solving. Azul solved the technology issues (or so they claim) but not the economics of it, and they solved it for a language that isn't a good fit for in-memory computing in the first place (to put it politely).
If I have to write software today that keeps a lot of data in-memory and requires reasonable latency (and I do) my only realistic option is C++.
I know all the drawbacks of naive reference counting. C++ shared pointers are a horrible kludge. Fortunately they are only needed in very few places, thanks to RAII and unique_ptr. The problem is that C++ has tons of other issues that will never be solved (antiquated modularity, header files, crazy compile times, excessive complexity and generally lots of baggage from the past).
I don't necessarily have a fundamental disagreement here, but I offer two caveats (one of which you may consider disagreement at a certain level).
One is that a lot of the discussion in this thread is not about what is possible today, but about where language implementations can realistically go.
The second is that there are language implementations that do allow you to keep lots of data in memory and still give you low latency; the catch is that most of them are functional programming languages and do not tie into the ecosystems of C++, Java, etc. which limits their applicability. But consider for example, that Jane Street Capital, which has pretty significant requirements for latency, is using OCaml. This is in part because OCaml has an incremental garbage collector for major collections (in addition to generational garbage collection). As I said, it's not rocket science.
The same goes for Erlang, which uses a model of thread-local heaps. Erlang heaps tend to be small (lots of threads [1] with little data each, even though the total memory footprint may be in the gigabytes), so Erlang can use a straightforward garbage collector that can run concurrently with other threads, does a complete collection fast (because the entire heap fits inside the L3 or even L2 cache) or can avoid collection entirely (if you specify the heap size explicitly with spawn_opt and no collection is needed before thread termination). As a result, Erlang can easily satisfy the low latency requirements for telecommunications (where its being used primarily).
Functional programming languages just had an unavoidable need for garbage collection for half a century now and so implementations of functional languages have seen a lot more GC tuning than imperative languages. Thus, you do at least in theory have other options, but I expect "realistic" in your case also implies being able to tap into certain existing software ecosystems.
Let me finally note that a big problem has arguably been too much focus on the JVM; not that there's anything wrong with supporting the JVM, but it has too often come at the cost of alternative execution models. JIT compilation, lack of value types, a very general threading model, loss of static type information, etc. all can very much get in the way of tuning automatic memory management. Luckily, some of the newer emergent languages target alternative backends, in part to avoid these problems.
[1] Technically, Erlang uses the term "process" in lieu of "thread"; I'm using "thread" to avoid confusion with OS-level processes.
http://dlang.org/statement.html#ScopeGuardStatement
and an article about it:
Note that if your language supports RAII and lambdas (e.g. C++11), it's trivial to implement defer using a class that takes a function as an argument to its constructor and calls that function in its destructor. So you can still have the flexibility of defer in a language with RAII.
Because "defer" is tied to function definitions, it means that pulling code out into a new function or inlining a function will silently change its behavior in subtle ways.
Like most complex language semantics, "defer" is less easily optimizable than the simple semantics of RAII—with RAII the compiler statically knows what it is supposed to call, which helps exceptions (panicking goroutines in Go) because it allows their cleanups to be optimized into table-driven unwinding. But because Go chose "defer", the compiler must insert code that dynamically keeps track of cleanups to handle the general case. This results in indirect function calls, and bookkeeping overhead, whereas RAII is purely static function calls. The bookkeeping overhead is significant: it allows RAII to be zero-cost in the no-panic path (very important in C++'s case!), while I don't see any way to implement "defer" in a zero-cost way.
That being said, D does not require the GC. It's easier if you use it for at least some of the features, but D makes it very easy to use RAII and manual memory management, which also helps a lot in making the GC work better, because it's much easier to avoid making a lot of garbage for it to collect when you don't need to. A lot of stuff in D ends up on the stack rather than the heap, and D's GC ends up having a lot less work to do than the GC does in languages like C# or Java. That being said, the current GC implementation needs some work (and effort is definitely put forth in that area), but if you don't want to use the GC, you can minimize its use or even outright avoid it (though _completely_ avoiding it can be a bit annoying since that means avoiding a few language features that require it; that list is short though).
So, while D definitely uses the GC and promotes its use where appropriate, you have full control over memory just like you would in C++. And the few features that are hampered by avoiding the GC don't even exist in C++ in the first place.
This is true, however there's a compromise involved. Because D also allows for manual memory management and unsafe memory access, it means that the GC is not free to move stuff in memory at will ... which really means that garbage collectors, like the ones available for Java (precise, generational, non-blocking, fairly predictable and compacting) are very hard to develop, probably next to impossible. This is the price you pay for using a lower level language and it's not a price that will go away easily.
I've been using Scala a lot for the past two years, using it to build high-traffic web services and while Scala is pretty wasteful in terms of allocating short-lived objects, I've been surprised at how well the JVM handles it.
In terms of throughput for example, Java GCs are much better than manual memory management. Allocating memory usually involves just incrementing a pointer, so it's basically as cheap as stack allocation. Deallocating short-lived objects is also fairly cheap, since it happens in bulk and so the amortized cost is pretty similar to dealocating stuff on the stack (!!!). The JVM can do some pretty neat things, like for example if it detects that certain references do not escape their local context, it can decide to allocate those objects straight on the stack.
What really sucks about garbage collection is the unpredictability. Java's CMS for example, awesome as it is, still blocks the world from time to time. And when it does, you have no real control over how much time it keeps the process hostage. The new G1 in JDK7 is much better and if you want the state of the art in terms of near-real-time GCs, you can buy into Azul's pauseless GC. But they still suck for certain apps. Allocating objects on the heap also means you have to pay the price of boxing/unboxing the references involved. This sucks too.
On the other hand, by having a good GC at disposal, it's much easier to build multi-threaded architectures. In C++ for example, it's so freaking painful to deal with non-blocking concurrent algorithms, or really, multi-threading of any kind.
Since I wrote a moving GC for Java years ago, and hence know how they work, I set the D semantics so it allows a moving GC. It's just that nobody has written one for D.
Took awhile to get used to, but it is a damned fine way to avoid memory leaks of any kind!
But even that aside, if you are writing something like a render loop with hard timing guarantees, (or anything else with timing needs!) having non-deterministic allocation costs can easily blow your cycle budget.
I'd just like to say there are sane solutions out there already to things like this. With the proper abstractions you get things like custodians[0] in Racket and several alternatives in terms of "call-with-..."[1] functions that do handling for you.
These might not be the languages that are being discussed here, but they offer things like these precisely because they are not the languages discussed here right now.
[0] http://docs.racket-lang.org/reference/eval-model.html?q=cust...
[1] http://docs.racket-lang.org/reference/file-ports.html?q=call...
- Sensible, pragmatic design decisions.
- dub + VisualD makes building code, managing dependencies and debugging painless for me.
- being part of building the ecosystem is fun
- I'm not comfortable with the high cost of developing in C++ (even with last revision) and never chose to use it in the first place. C++ is basically forced on me since years.
- I feel like I can be more productive and write higher quality programs when using D. I can use RAII in D like I would in C++.
- I feel like Go and Rust do not address C++ shortcomings while introducing problems of their own.
- D programs are short. I don't need nor want IDE refactorings.
- I missed templates based on any value/symbol, it forced macros on me in my very first try. I don't think it's a problem once you know Rust, but having to write macros was too intimidating for a newb.
Compilation speed remains a work in progress; it's improved a lot in recent versions. Note that 80% of the compilation time in rustc is actually in LLVM passes (the same used by clang), which are mostly optimizations, so turning off optimization helps Rust compile times a lot. LLVM as a backend does many more optimizations than DMD (and 6g/8g for that matter) and runs slower as a result.
One issue is that Rust currently does not do incremental compilation below the crate level, so you will need to use many crates if you want incremental compilation. This will possibly change at some point via a ccache-like mechanism.
If memory safety is not important to your applications, though, then Rust may indeed not be the right choice. Rust requires you to make sacrifices (a learning curve and less flexible unique pointers) to ensure memory safety, and if you just want to write "new" and "delete" then Rust isn't going to be the best language for you. (That said, I think there is a strong argument to be made that for many classes of programs it is worth some pain to eliminate memory safety problems, because memory safety issues frequently lead to security vulnerabilities. For us as browser manufacturers, memory safety is so important it is worth sacrificing literally everything else except maybe performance in some cases.)
> - I missed templates based on any value/symbol, it forced macros on me in my very first try. I don't think it's a problem once you know Rust, but having to write macros was too intimidating for a newb.
In general you want to use traits instead of macros to write generic functions. There are some current limitations with traits but I think they're a more scalable approach than ad-hoc templates. It'd be helpful to know exactly what limitations you were hitting.
> Note that 80% of the compilation time in rustc is actually in LLVM passes (the same used by clang), which are mostly optimizations.
OK I had a flawed perception probably because of this.
> That said, I think there is a strong argument to be made that for many classes of programs it is worth some pain to eliminate memory safety problems
I agree 100%, especially on teams memory safety become incredibly important, also I have to thank you for fixing C integer promotion which I've seen create many bugs.
> It'd be helpful to know exactly what limitations you were hitting.
Trying to implement a "small vector" structure is my "hello world" program to get to know a language, and Rust implementations of it uses macros. https://github.com/bjz/cgmath-rs/blob/master/src/cgmath/vect... https://github.com/sebcrozet/nalgebra/blob/master/src/struct...
Maybe not crazy difficult once fluent in Rust, but a bit scary for the beginner.
Finally, I like ad-hoc templates so it's a bit hard for me to get out of this mindset, which might not be the best like you said.
You can use RAII all you want in D. The D standard library uses it for things like Files, containers, and smart pointers. I feel like Garbage Collectors have become something of a bogeyman for native languages. There is a lot of value a garbage collector can add. In D it's rarely hard to switch to managing your own memory if your profiler shows the garbage collector taking up more time than you'd like. For most programs avoiding the garbage collector is a premature optimization though.
For IDEs you have: - Mono-D http://mono-d.alexanderbothe.com/ - VisualD (should be included with Windows DMD in the next release) https://github.com/D-Programming-Language/visuald - Code completion for a variety of editors including vim, emacs, SublimeText2 , Textadept, and zeus. DCD https://github.com/Hackerpilot/DCD
The DCD utiltiy can drive the code completion for a bunch of editors/IDEs.
https://github.com/Hackerpilot/DCD
It works well.
I was using the other standard library (yeah, there were two, kind of), there were bugs which weren't resolved for years, there were issues with people camping on both sides of standard libraries, there was development stagnation because D2 was being pushed hard... but it all boils down to preference.
D1 (with Tango) to me was like a really really good blend of C with classes and modern stuff in it (mixins for example). I was happy with it, but then D2 started to emerge which was more templatey than I was comfortable with. I have accepted, long ago, that I am a C programmer, not C++, by heart. Ultimately following factors threw me away from D altogether:
- my code isn't an island, I leverage a lot of libraries, and for each and every one I had to use I had to either make my own bindings or rely on somewhat unstable other people's bindings. I accepted the reality of it, but it wasn't something I wanted to waste my time on.
- D2 - it just didn't feel the same
- Lack of tools. DMD compiler, while somewhat working, was a lackluster (to be polite) compared to what I was used to in C world. There was a GDC frontend for gcc which, at the time, wasn't actively developed, there was an attempt to make a LLVM thing.. but if you wanted to work with D, at that time, you pretty much had to use DMD
- several bugs which were ignored in core development which were uncomfortable for my use. I didn't have the expertise at the time to help with resolving that. Coincidentally just yesterday I received an update from bug tracker that bug I reported four years ago is still in.
- Development of D pretty much relied on one man alone
- out of frustration and a tight deadline, I developed something in C at that time and came to a realization that "it just works". I was able to concentrate on my task at hand instead of tackling various gotchas and doing extra amount of work that I had to with bindings etc.
D is more than 10 years old. Honestly, I think it has good ideas, I really liked the approach of D1, but I think it will never catch on en masse.
That said, D has a lot of promise, and a lot of these issues have been worked out, but I feel like there are many people like you and I...
I'm not sure. I haven't worked on it in a few years, the others may be keeping it going.
History proves that the only system programming languages that succeed in the industry, have been at a given moment adopted by OS vendors as their main language.
It hasn't happened so far to D, but it might still happen.
Then there's the history thing about Java being designed from the start to run devices: http://www.oracle.com/technetwork/java/javase/overview/javah...
I am fully aware of JNode.
It uses language extensions for the dirty tricks system programming languages need to do.
> Then there's the history thing about Java being designed from the start to run devices:
The devices are expected to have a ROM installed VM able to process the bytecodes. Which is the case of many devices that have Java VM available.
Until sun.misc.Unsafe or similar is not officially part of Java's public API, the language does not offer standard mechanisms for systems programming.
There are language extensions that allow such uses, but the language itself, according to the JLS does not support systems programming.
You need:
- value types
- control when a GC might happen, to avoid it ocurring during interrup handling
- means to tell the GC not to touch memory currenly involved in DMA operations
- all the nice operations sun.misc.Unsafe provides
The Tango/Phobos split has been resolved for awhile. You can now use Phobos, Tango, or both in the same D2 program.
The number of libraries and bindings is growing rapidly. There is the new dub package manager that makes it easy to include dependencies < http://code.dlang.org/ > and Deimos which is a collection of C library bindings < https://github.com/D-Programming-Deimos/ >.
GDC and LDC are both actively developed and kept up to date with the state of DMD.
It used to be you'd usually hit a bug while working on something in D but the community is really starting to notice they aren't hitting many bugs these days (especially over the last year or so). < http://dlang.org/bugstats.php >
Everything is up on Github now < https://github.com/D-Programming-Language > and Walter is just one of 21 committers. Github says dmd has 72 contributors and Phobos has 116.
If you don't like D2's template approach though you probably still won't be happy with it even with almost everything being better. Personally I love the power it gives you without sacrificing speed.
"Aside from speaking whether 5112 lines of code is really a good sign, there is separate issue regarding quality. When you will look at claim that some language (lets take for example C# or Java) "supports feature X", that really means that the feature is supported. In D this for sure means that the feature is either broken or misdesigned (shared libraries, routine code breakages, obsolete ms32 object format, AA arrays, shared, const postblits, odd template crosstalk bugs, type system holes, segfaulting lambdas, unstable stdlib, absent of third-party libraries). Untill this stuff is fixed this is a huge barrier irrespective of whether D is used in Facebook or not."
The situation is better and greatly improving. Many things have a work around. It is just one of the problems with a language full of tools and little full-time man power. Java and Go are rather simple languages so there aren't as many features to boast (e.g. not supporting shared libraries is a feature of Go, yet "broken" in D [lots of good work in git HEAD])
Now, I'm less clear on how D2 compares to C++11. Certainly some of the smaller improvements matter less, as C++11 has them.
The drawbacks today are in my eyes mostly the relatively minimal support for non-PC platforms and that a number of language features are not yet completely finished. But if the main target are x86 based systems and the use of cutting edge features is not the primary concern, D2 is a great development tool today.
* I can only really talk about my experiences going from C++ -> D, but it was a long process where my way of designing systems and solving problems was gradually altered in many areas - much to the better. And the immediate reward of course is the extreme gain in productivity due to concise syntax, fast compilation times and, last but not least, the lack of a need for header files.
The D community has greatly pushed D away from this initial improvement. In C++ there is a separation of the developer tools and the library writer tools. I think that separation still exists in D, but it is in an area even library writers don't/can't reach for in C++.
Ultimately D doesn't force a fundamental change, but as one learns to use the language, the result is a fundamental change.
Right. One can do a line by line translation of C++ to D, but idiomatic D can be very unlike C++.
Note that I live in a startup environment all the time and the time and cost to develop in C++ is just too damn high for me. Also, the verbosity and its philosophy kills me.
What was it?
std::map<int, std::vector<int>> whatever = new std::map<int, std::vector<int>>();
d = {}It's a lot shorter, actually correct, and it's totally cool to import whole namespaces in a .cpp implementation file where you're likely to actually declare something like that.
If you're going to critique the language you should try to learn it first.
d = {}
auto whatever = new std::map<int, std::vector<int>>();
auto whatever = new map<int, vector<int>>();
map<int, vector<int>> whatever;
auto whatever = new std::map<int, std::vector<int>>();
std::map<int, std::vector<int>> whatever;
But lets look a bit deeper why C++ is more verbose in this case. One central reason is the idea that standard library should not be special/privileged in the language syntax. The upside from that is that almost all syntax sugar can be applied to user defined types. A relevant example would be uniform initializer lists in C++11, which allow you to write eg.
std::vector<int> foo {1,2,3};
MyFunkyDatastructure bar {1,2,3};
The theme of non-privileged standard library also extends to global namespace pollution. In C++ stdlib does not get to reserve names at global namespace, which leads slightly increased verbosity (std:: -prefixes or using-statements).
So when you ask why you cant make a map/dict in C++ with just 'd = {}', know that there are actually good reasons for (some/most) of the verbosity. The tradeoffs might make it less suitable in your usecases, but there is no absolute/general superiority in either way.
This is why I talked about the philosophy of the language. I wasn't arguing about whether it was good or bad.
That being said, for my own use cases, verbosity is a big deal.
>> In C++ stdlib does not get to reserve names at global namespace, which leads slightly increased verbosity (std:: -prefixes or using-statements).
I understand and agree, but you'd have to agree with me that if you start naming your classes Map and Vector, you're looking for problems ;-)
1. You picked probably the most verbose way to do it.
2. It's not valid C++ because you're assigning a pointer to a value.
3. Idiomatic C++ doesn't use `new` explicitly anyway
4. The `d = {}` of Python is not really equivalent.
My feeling is that python gains brevity in exchange for putting a heavier mental load on the programmer, which is manageable for small programs but becomes unwieldy for larger ones.
int[int] whatever; int[][int] whatever;
whatever[1]
map<int, vector<int>> d = {{0, {1,2,3,4,5}},
{1, {6,7,8,9,10}}};So I'd imagine it has something to do with said expertise.
Go is targeted for developers that can move out of C in their use cases.
D is targeted for developers that can move out of C++ in their use cases.
However, I quickly became disappointed with Go's spartan design, given my broad experience across languages and paradigms.
That is why somehow I feel it is more indicated for C developers, that could live with a GC enabled language.
As they would mostly getting type safety and a few more features, whereas developers from other languages are mostly giving away features.
I've always much preferred C style to C++/D/Rust based mainly on readability and how small the language felt. I completely agree though that Go has given me this similar feeling - to me it really is a modern C. That said, I'm not sure how many C devs are going to like the bounds put in place by Go, or the mandatory GC.
I am, admittedly, a big fan of go also. For me, it has taken from both C and Python use cases, which I think says a lot about its versatility.
The D statement may be accurate, I've never done anything with D and only minimal brush ins with C++ - but to my untrained eyes, they seem pretty similar.
That doesn't mean that it's stable, it's just that we do know what it looks like.
D also owes more of its ancestry to C++, while Rust takes a lot of its inspiration from the ML family of languages.
Both languages are gunning to appeal to C++ programmers, and they're both worthy in this regard depending on your use case. The C++ pie is more than big enough to let both languages thrive independently (and their underlying philosophies are different enough that I expect very little overlap between their communities).
(Disclaimer: I work on Rust, among other things.)
> The project is in heavy daily use at Facebook
So, they had code under heavy use which was not under source-control?
Sometimes I wonder how computing would look like if the default implementations of Java and C#[1] were available from the start as native compilers, instead of VM environments.
[1] Funny enough, the precursor of .NET was native and COM based, similar to what is now WinRT, more info here,
http://blogs.msdn.com/cfs-file.ashx/__key/communityserver-co...
I think that's why the GP has the JIT in parentheses (to account for Julia's implementation, which does use a JIT-compiler, as opposed to D and Nimrod)
At least with Java that would defeat one of the main intents of its development. What would you think would be gained by having non-VM based implementations of these by default?
For the JVM, considerably lower startup/JIT warm-up times. You can really observe this nicely if you're using Zinc (the incremental Scala compiler), where you not only cut the startup overhead down to pretty much zero, but compilation really speeds up once the JIT has warmed up a bit. (Hence why Nailgun exists.)
Nailgun seems to be a way to keep the JVM running so you don't incur the startup overhead. Straightforward enough, and makes sense when your execution time is dominated by the JVM init.
Zinc seems to be a compiler based on Nailgun so that performance improves over time (particularly useful for long compiles or frequent compilation).
Neither of those though, move Java off a VM/JIT basis. However, as someone who hasn't seen them before, it was interesting reading and neat to see what's going on in the rest of the world.
That's the thing; the Nailgun workaround to an extent avoids the startup overhead, but can create other problems. E.g., when you're starting multiple builds on the same server (because the Nailgun server listens on a port, so you may have to sort out conflicts), if you have multiple users on the same machine (because anybody can connect to the socket, so you have a potential security problem), etc.
With a native option, this can be avoided (note that IBM offers an AOT compiler for Java).
Re: Nailgun - that seems like an implementation issue, but yes, if native compilation were present then Nailgun wouldn't exist (or need to) so the technical issues causing those problems wouldn't exist.
If you mean bytecode, well there isn't nothing speaking against it. After all it is just an implementation issue.
And bytecodes are not Java specific. Pascal, Ada, Modula-2 are languages with native compilers that also had originally bytecode compilers as well.
But most importantly, it would not confuse a whole generation of developers to mix strong typing with VM as form of implementation.
Many people discussing about languages in HN and reddit, tend to first of all, mix languages with implementations. Language X is compiled, interpreted, ..., sometimes without knowing multiple implementations are available.
Then many never used strong typed languages with native compilers, like Pascal, Modula-2 and so on. Their experience tends to be limited to JVM/.NET languages.
Outside of this world, they kind of know C and C++ are not as strong typed as those languages, don't have a GC and have native code compilers available.
Hence, strong typed typed languages are managed and require a VM.
This is a pattern I observed in many young developers without CS background.
This was the initial way Pascal and Modula-2 were developed. P-Code and M-Code were their bytecodes.
This didn't prevent most compiler vendors to introduce native compilers and use those bytecode implementations mainly for bootstraping purposes.
Writing compilers is not that dark magic thing many think about.
Well, except when targeting x86 processors, maybe. :)
You couldn't write an operating system, or realtime code in C#.
It's not even in the same league as the other three, and would be better compared to Java.
This is not true. The CLR is just one of many C# implementations.
Mono provides a native compiler for C#.
Bartok is a native compiler for C# from Microsoft Research.
> You couldn't write an operating system, or realtime code in C#.
Except people have already done it in the past.
http://research.microsoft.com/en-us/projects/singularity/
http://research.microsoft.com/apps/pubs/default.aspx?id=5271...
http://singularity.codeplex.com/
> It's not even in the same league as the other three, and would be better compared to Java.
Similarly to Modula-3, C# has all the required low level capabilities for systems programming with unsafe blocks and annotations.
It should be compulsory for everyone to learn about compiler design, before comparing programming languages.
That said, I stand by my argument that it is better compared to Java, though the later revisions have been adding more C++-esque low level features. I find C# a good compromise.
> It should be compulsory for everyone to learn about compiler design, before comparing programming languages.
My oversight, and difference of opinion with you does not mean I'm an uneducated idiot. I wrote a (limited) C compiler in my undergrad and programming languages was large mandatory portion of 4th year. If you rear-ended somebody on your morning commute, I'm not going to assume you're a dangerous driver and should be pulled off the road.
This is Hacker News - not Reddit. The least we can do is act like that means something.
I think Andrei is being clever more than anything. They're all different in many ways.
That's what I was attempting to convey, not any similarity between the languages themselves (the erroneous and unfortunate mention of C++, notwithstanding).