Modern C++ is a very different language though it can still almost completely interoperate with quite old code. C++11 and C++14 already addressed most of the things brought up, and contemporary C++ (obviously most code is not in it yet) even supports generic template functions with a straightforward syntax (i.e. use auto instead of <..>).
Being generous:
* There's now `std::string_view` to address some of the problems with `std::string`, but the rest are still there. There are some attempts to specify the encoding now, at least.
* Lambdas and `std::function` pretty much solve the function pointer complaints, with some added complexity.
* Containers still do silly things when you use `c[..]` syntax with no element there. (Both when trying to insert and when trying to retrieve!)
* The general level of language size and complexity, especially around templates, has only gotten worse. Concepts will finally help in some ways here.
The author, after a long and dubious appeal to authority, claims that:
* C++ exceptions are outright evil and should be avoided
* C++ string class "is so utterly godawfully stupid" because it has no garbage collection or refcounting, and in short doesn't precisely match Python's implementation. He also felt personally insulted by the fact std::string is a template class.
* He feels C function pointers are fine but believes function pointers in C++ weren't extended to support pointers to member functions, which he then backtracks and says they actually exist but they are "so horrendously ill-conceived that absolutely nobody uses it for anything", thus showing his ignorance and lack of experience.
* For some reason he criticised std::map for the way it's std::map::operator[] returns a reference to the mapped value, eventhough that's what it is supposed to do by design and by the principle of least surprise.
* The author made other claims, but the text grows so much in the style of "foaming from the mouth" that it's just better to stop reading after a point.
In short, this article is just a rant where someone vents that a programming language other than Python is not Python at the eyes of the author. It's a pretty unconvincing rant and full of logical and rational holes, but a rant nonetheless. So the author loves Python and his personal take on C++ does not match his view of Python. That's fine. It's just weird how this sort of text floats up in a technical forum after over a decade after it has been published, as if it's expected to add or say anything of value.
FWIW, I find std::map operator[] creating an object extremely convenient and it is very annoying having to use defaultdict to get the same behavior [edit: in python]. So ugliness really depends on what you are used to.
> The general level of language size and complexity, especially around templates, has only gotten worse. Concepts will finally help in some ways here.
variadic templates and type deduction greatly help. A lot of complex template metaprogramming is suddenly not needed anymore (I've used boost::mpl a lot in the past, but not once in the last 10 years). constexpr functions also helped get rid a lot more use cases. Finally if constexpr made a lot of sfinae hacks obsolete.
(In old man voice) We ended up rolling out own stuff and marking std:: verboten. Why? Stl was too slow, too verbose, and too hard to grok the stack when debugging. We ended up with less memory fragmentation, less dangling ptrs, etc etc. In the rare case there was something in STL that was actually cool (or faster, which was very rare), we'd gut it and reef out the part that was cool to use in our implementation.
I presume these comments aren't popular (sorry about that, but this is during 90s and early 00s when dev cycles were clearly different). Eg. We had string classes in all different flavours, some would interop, some wouldn't. Eg. We had tree and hash classes that, while templateable, had a few core implementations that made compilation fast. We had various ptr management systems (ref counted, stack based, etc).
We made STL between verboten in all APIs because we been burnt so many times using (/trying to use) other ppls APIs that exposed STL in its library. (We were exclusively a windows shop, if that helps understand my confusion... PS. I'm retired these days and have been out of the c++ game >10yrs)
This is surprising for Java devs, but given that value semantics must be supported, there's no way to avoid it.
In that respect, the author probably wouldn't be happy with modern C++, either. For example, C++ is never going to be a garbage-collected language (by default, at least). Modern C++ gives you better tools to deal with that, but the core design concerns that make C++ the way it is haven't gone away.
”Garbage collection (automatic recycling of unreferenced regions of memory) is optional in C++; that is, a garbage collector is not a compulsory part of an implementation. However, C++11 provides a definition of what a GC can do if one is used and an ABI (Application Binary Interface) to help control its actions.”
Whether that feature is a good idea or not and to what degree, is the question.
You can write your code in modern c++ and ignore prehistoric carbuncles (some of which have been deprecated and eliminated FWIW). And you can call external code written in older dialects without having to look into its source code.
This is not what happens in the real world though.
While I agree that you have to deal with whatever is in your codebase at a given point, it also doesn't imply that you have to use everything and that everything can be useful for your project.
As standards keep coming and features get added, it's still increasingly prevalent to see guidelines and awareness around the topic of choosing your own subset of C++ to work with.
The main drawback is mostly that it incurs a cost in terms of brain power to discipline yourself to keep your work within a restricted set of language and standard library features.
It's extremely rare (and even debatable) whether a single person masters all the aspects and features of C++ (and if there's one, it's probably Alexandrescu).
That makes as much sence as claiming that to develop software in, say, Python on the real world you have to learn and deal with all of its standard library.
That is not the case. That has never been the case ever for any programming language, be it large or small. Specially in C++, where since it's inception the standard approach is to, at best, adopt a subset of all features and stick with it.
Maybe C++30 will have fixed everything...
If not, then... the above statement does not stand.
Before I started refactoring I decided to make everything 'less ugly' by moving it to C++17. Which would also help me get back into the code, after eight years.
I spent two days on this. Then I decided: fuck it. I will RIIR™.[1]
It will mean that it will take me at least two months to get a beta of the product with feature parity vs. maybe a week to port the old codebase to the new API.
But on the other hand the C++ code is littered with stuff that 'just works' but can explode in your face and which eventually needs some safety net written around it. Which will likely take at least two months to do properly.
The truth is: after one and a half years of Rust C++ feels painfully ugly.
For context: I started with C++ with Borland's TurboC++ (moving from C) when I was 15. I used C++ for almost 30 years by now. It's about time.
[1] Yes, I did read http://adventures.michaelfbryan.com/posts/how-not-to-riir/
using Callback = std::function<int(int)>; // or whatever
Callback cbk = [&](int i) { return instance.method(i); };
Using various bind equivalents just requires you to know what you're doing:
boost::function<int(int)> cbk = boost::bind (&SomeObject::some_method, instance_of_some_object);
...
cbk (22); // invoke callback
In addition, the author's complaints about nobody using ptr-to-method is absurd. Even in 2010, anyone using libsigc++ or its (few) equivalents was using them, which meant that any GUI app written using GTKmm was full of them. What's not to love?
Callback cbk = std::bind_front(instance, Instance::method);
Here's the D<->C++ intercompatibility project: https://wiki.dlang.org/Calypso#Current_status
the irony is that in 2010, many std::string implementations were in fact reference counted (including libstdc++). This was generally considered a major mistake (because it doesn't work well with threads and when it does is a major performance pitfall) and prohibited in C++11.
https://twitter.com/apenwarr/status/1232848468156256256?s=21
[The [] operator] is an absolute
failure of engineering!
Do you want to know what real
engineering is? It's this:
map_set(m, 5, "foo");
char *x = map_get(m, 5);
This is the power and achilles heel of Lisp as well.
Mindshare - Lisp has its zealots. C++ is tolerated rather than adored, because it's more of a Katamari Damacy of stray CS than a language with a coherent focus.
How many other languages have a Turing complete sublanguage built into them just to handle templating?
> But in python, it works perfectly (even for
> user-defined types). How? Simple. Python's parser
> has a little hack in it - which I'm sure must hurt
> the python people a lot, so much do they hate
> hacks - that makes m[5]= parse differently than
> just plain m[5].
>
> The python parser converts o[x]=y directly into
> o.setitem(x,y).
Lisp has generalized variables via "setf macros", which turn assignments into the right set of calls to setter functions. Setf macros do this at compile time and generically for any getter/setter functions that have been registered with a bit of ceremony.
(Lisp also has destructuring-bind, which lets you write a data structure with variable symbols in it such that the corresponding variables will be bound to the data find in the corresponding places of a real data structure value. The two features, destructuring and generalized variables, are similarly magical.)
jq can do crazy generalized variable assignments like '.a[].b[0] = 1', but this is a run-time thing. (The LHS is evaluated in a context that allows only "path expressions", and in a reduction, while the RHS expression is run in the body of the reduction to update the input value at each path matched by the LHS.)
Icon implements generalized variables by letting procedures return "places" -- references to assignable locations --, so you can assign to the return value of procedures. This may seem quite surprising when you see it, but it works beautifully.
If you ever design a language you should hope that it gets popular enough that people bitch about it this hard. That’s a real triumph.
> If you've heard anything about C++, you've probably heard that there's no standard string class and everybody rolls their own.
Is this still true? std::string seems perfectly reasonable now, especially now that they've given up on supporting ropes and integrated the small string optimization. Yes it doesn't specify an encoding.
> No garbage collection? Check. No refcounting? Check. Need to allocate/free heap space just to pass a string constant to a function?
Nothing else in the standard library is garbage collected or refcounted by default. Why would std::string be the lone exception? You can opt into refcounting for any type using std::shared_ptr.
The objection about allocating/freeing heap space is about APIs that take const std::string& being passed C-string literals. Legitimate complaint, but it's addressed by std::string_view now.
> ...rant about lack of []= operator...
[] mutating the map does surprise people, so that's definitely a legitimate complaint. And it is annoying to have to use find() in a const context...
but simple operations like counting are simpler and more efficient in C++ than in Python because the +=, -=, etc operators work:
for value in list:
counts[value] = counts.get(value, 0) + 1
for (auto& value : list)
counts[value]++;
This is just comical. Python is not playing in the same performance league as C++, regardless of whether inlining or RVO happens. RVO of course is a general optimization for returning objects by value from functions, not a special case to optimize setting map items. It's still relevant, but less important since C++11's move semantics.
"You can't make C++ beautiful, but you must try."
I don't see why not? You'll have to decide the ownership semantics if they're dynamically allocated but that's it?
Not ugly is more of a less strong "pretty" and can't not is more of a "should" (rather than "can"), so the title can be read as "you can't make c++ pretty, but you should try (to make it pretty)".
I would rather use C++ because i would have the option to use abstractions like std::map, std::string, std::vector, std::any etc. as they would save a lot of time and code complexity.
IMHO the worst thing about using C/C++ is getting other libraries to play with your project well even if you are using cmake or vcpkg, its not enough. You have to have solid knowledge of each operating system class to get everything working nicely over the long-term.
That depends on how you write it. It’s possible to write C++ that bears no semblance to C whatsoever. (I have done so for effect; I once assigned some students to write a C program but wanted to provide a reference implementation with source so I gave them one in C++ that wouldn’t translate directly at all.)
Why would you ever want this? Gives me Java nightmares.
(I wonder how many of these posters are real or fake. Given the karma and post of this poster I'm inclined to... wait. Last comment was in 2017. Yet... hasn't too many posts since that, I think it's about 4. Probably a bit out of the loop, buy maybe not malicious.)
Please see https://news.ycombinator.com/item?id=22429925 below.
[...] Please don't post insinuations about astroturfing, shilling, brigading, foreign agents and the like. It degrades discussion and is usually mistaken. [...]
And if you're a Dirty Harry type like me, debugging issues with dozens of disparate codebases written in various crap subsets, you pretty much have to know the whole cursed thing.
Also known as a debate.
Beyond that, even the "good" modern subset of C++ is crazy complex. I've sat in a room with some of the better C++ programmers in the world while they study and try to comprehend the new features like rabbis interpreting the Talmud.
If there's one concise, fundamental rule of software engineering, it's this: Complexity kills.
But it sounds like what you want is a "handle" or some such term, by which you can invoke a member function on an object, and all you need to do so is the handle. That's a different problem than pointers to members are trying to solve, but you can do that quite easily with a function object. That's essentially a roll-your-own closure, and since you can define whatever data members you want, you can close over anything.
One thing you have to watch out for, though, is lifetimes. C++ is not garbage-collected, and so it will not preserve an object just because another object has a pointer or reference to it. If you create a function object that captures a pointer to member, and a "this" to invoke it on, and the "this" gets destroyed, and then you use the function object, you're going to get chaos.
Adding behavior to replace a NULL/None return with a default object is pretty easy.
Removing the default object that you've been inflicted upon... how would you go about that?
Is there a list somewhere of features that have actually been removed from C++? (i.e., that would cause old code to break)
Rust isn't but D is absolutely a garbage collected language. The GC is provided by default and expected to exist. https://dlang.org/overview.html#resource & https://dlang.org/spec/garbage.html
There's a non-GC'd subset of D, though. That would be the BetterC subset https://dlang.org/spec/betterc.html
The article is indeed still relevant.
He'd have that in C too, and that's the expected behaviour. What he would want is:
#define STRING1 "hello"
#define STRING2 "world"
const char* gString = STRING1 " " STRING2 "!\n";
#include <stdio.h>
int main() {printf(gString); return 0x0;}This is all due to C compatibility.
There's some overlap between C and C++, but maybe this wasn't such a case? Sorry, if it was uncalled for.
But on the other hand, even some of these less-helpful points have an element of truth:
* A lot of people/domains/codebases do wind up avoiding exceptions, for good reason. There is even an active proposal to provide an alternative kind of exceptions to solve their problems!
* Member function pointers are quite a mess, introducing a lot of complexity by not being compatible with regular function pointers. It wasn't until long after this article that those incompatibilities were papered over with the standard library.
* std::map::operator[]'s behavior arguably does not follow the principle of least surprise- it's a giant footgun.
The author goes out of his way to point out that the changes he wants don't require GC or an interpreter, despite all the comparisons to Python. It's not an insubstantial comparison in that light.
> The author [...] claims that C++ exceptions are outright evil and should be avoided
What the article actually says:
> This includes the RTTI and exceptions stuff; C++'s versions of those were enough to convince a whole generation of programmers that introspection and exceptions were outright evil and should be avoided
Your reading comprehension is lacking. You didn't understand what he is talking about. Why is Google not using exceptions?
Btw, that code is using std::unordered_map which is notoriously slow compared to an ordinary std::map for a small amount of elements. And the unordered map of register names each with a pair, why? Why not use std::vector for fast lookup?
The crux of what i'm saying isn't anything new, Bjarne Stroustrup admits that C++ is mainly a high-level abstraction language. There is some new things, but really, the things that are new like << etc. are operator overloads which are just more abstractions.
I suspect this is not an uncommon situation among programmers.
"No true Scotsman" and all, please refrain from posting messages that add nothing of value besides petty insults thrown in broad brush strokes.
So when you go to another project that made different decisions, what you should do is understand the decisions. It's quite easy. And that's why it's what people do do, and it's why people are capable of contributing to projects other than their first.
If you program in C++, it's the same skill you used to learn one or more of {CMake, Makefiles, scons, bash, python} except it's easier because you already understand the programming language's model.
On the bright side, C++ doesn't have obscure keywords like "cdr" and "car" that refer to specific hardware elements of an obsolete computer built in 1954.
Significant whitespace means that we can't reliably use a traditional whitespace-insensitive diff to to compare changes in Python code that seriously change its meaning, such as change how many statements are in the scope of an if.
This is the funniest and most accurate description of C++ that I have ever heard. +100 for the game reference.
D does. It's just that nobody uses it for that, because CTFE (Compile Time Function Execution) is so much better.
“There are only two kinds of languages: the ones people complain about and the ones nobody uses.” ― Bjarne Stroustrup
A language does not need to be adored, it just need to do the job and have users.
Every language has its quirks, if they are not obvious enough, it just means your language is too young for now.
Languages/Frameworks with their zealots, evangelists and fanatics are generally the ones that will probably disappear in less than 10 years.
"coherent focus" (often mean dictator driven) never survives the test of time.
About mindshare: Lisp has zealots, but they are few, even if they are loud, and they are on HN more than many other places. C++ is perhaps not loved, but in some circles it is very well respected, the way a chef respects a very sharp knife. The value lies precisely in the sharpness.
I'm out of my depth, but I'm pretty sure HM is not Turing complete by design as otherwise it wouldn't be able to guarantee that inference completes. An HM type system is about as powerful you can get without being Turing complete.
There are extensions to the type systems of languages that use HM making them Turing complete, but when using those extensions inference is not guaranteed or doesn't work at all.
For lower-level programming, while my favorite is Rust, if I cannot use Rust for some reason (say the team against it) I'd use C++.
To be sure, what I mean is I would use my favorite subset of C++, and I adore that subset. The parts of C++ outside of my chosen subset are merely tolerated.
Picking up features in a language you already use is easier than learning the language to begin with which itself is easier than learning to program at all. If you were able to read the documentation to get to 50%, you have all the skills needed to pick up the rest and get to the difficult part of picking up a new project: understanding the problem space. If you're capable of learning the meaning of an API you've never seen before - and you will, if you're not writing your last project verbatim - then you're capable of learning what a lambda means. This is not me saying that all programmers should be able to do this, it's me saying that doing this is a predicate of engineering software.
You accused anyone who did not agreed with you of being incompetent and immature. In the very least own your own claims.
std::string is in the STL. So is std::string_view. There are language changes as well that enable some of the new STL additions but some are just STL updates and you could "backport" them so to speak. Or do the same thing but yourself.
Making std:: verboten these days would likely be a mistake, though. There's so many things that are just not controversial and not worth re-implementing. Like std::unique_ptr. Or std::array.
Most of the containers are still better off ignored, though, many of them unfixable. The least worst of them is std::vector and it's still _ok_ but even there things like absl::InlinedVector are worth a strong consideration instead ( https://github.com/abseil/abseil-cpp/blob/master/absl/contai... ). Or boost's small_vector ( https://www.boost.org/doc/libs/1_60_0/doc/html/boost/contain... )
std::map, for example, is only appropriate if you need a red-black tree specifically. Which almost nobody does. std::unordered_map is less awful, but abseil has a literal straight upgrade. With the same API. So... why would you pick the slower thing when you're using C++? std::vector is only really appropriate if you know you never have small vectors, which is again a more obscure situation.
Not sure which part of std::string you're referring to but the compiler generally doesn't contain any knowledge of the library itself. It does goes the other way though where the standard library has to know how to implement certain functionality on a given compiler (some type traits functionality IIRC isn't possible to implement without compiler builtins that expose the AST to you). I think Rust has taken a more sustainable approach with their macro system which can modify the AST instead of relying on builtins but even in Rust I suspect they use builtins in certain places of their standard library.
Today's STL implementations are going to be better performing and more robust than anything you'd write yourself so generally a good idea to stick to it as a rule of thumb for the majority of code.
There are places in the rust standard library which just omit the implementation because it's magically filled in by the compiler based on the type and function names. Which, for really low-level and fundamental functionality, seems fair game to me.
* various operator new * all the type traits * a lot of the names inherited from the C library
compilers could do much more, but in general they prefer to implement generic optimizations instead of targeting a specific library name (for example removing allocation for stack allocated std::strings was not done until the generic removal of alloc/free was implemented).
I believe some standard-library type-traits cannot be implemented without specific compiler support.
[0] https://github.com/boostorg/type_traits/blob/059ed883/includ...
I think that’s still pretty common, especially in game development and/or when compiling with exceptions disabled. AFAIK std::vector is fine, and probably std::string, but for things like std::[unordered_]map, Abseil and Folly have equivalents that are slightly non-standard and much faster.
That assertion makes no sense at all. The stl contrainers work very well as basic generic containers that can safely be used for pretty much any conceivable use where performance isn't super critical. I'm talking about cases like, say, you need to map keys to values but you don't really care about performance or which specific data structure you're using. That's stl's domain: robust, bullet-proof implementations of basic data structures that are good enough for most (or practically all) cases with the exception of a few very niche applications.
If you happen to be one of the rare cases where you feel you need to know if a container is built around a red-black tree or any other fancy arcane data structure, and if this so critical to you that you feel the need to benchmark the performance to assess whether you either need to use non-defaults or completely replace parts or the whole container with a third-party alternative... Then and only then the stl is not for you.
You're arguing it's better to use something that's across the board worse for nearly every user, and by a lot, just because... why? It's slightly more convenient?
It really isn't. The whole STL is, by design, a template library packed with generic data structures that are designed to have very robust defaults and still be customizable and extensible.
When the defaults are good enough, which is the case in general, the STL will do. If you have a niche requirement (say, games) or feel adventurous, you adopt custom and/or specialized solutions.
This has been the case since the STL's inception. They are the standard, default library. I can't understand how someone is able to miss this fact.
There are lots of subtleties STL containers have to worry about in designing containers, regarding everything from iterator & pointer invalidation to allocation and allocator propagation. All this is because they're designed to be general-purpose and support most conceivable use cases. Their replacements have to trade off requirements in order to get better performance or otherwise improve on some axes.
It only breaks swap of the container itself during iteration. Which is a super niche condition.
And that swap also invalidates some of std::vector's iterators as well - specifically the end() iterator.
> They also really only make sense for tiny objects (ints, etc.) given you don't want a pickup truck's worth of data on your stack. They're most definitely not general-purpose.
Of course they are still general-purpose. They can (and do) specialize on the size of the object being contained. The only reason std::vector doesn't also have SSO is because it's an ABI break. Not because it's better in some way or less fragile. Legacy is the only reason.
And they don't invalidate the iterators that point to actual elements, which was kind of the entire point I was making. Don't let that stop you from trying to make it look like I'm just blurting out nonsense, though.
std::function is fine for prototyping, but its size hit is extreme, so in embedded code we use other implementations. But where size and speed doesn't matter? Why bother?
These are all largely header libraries. You're already hauling in a dependency, and in every c++ file that uses it at that.
> std::function is fine for prototyping
std::function isn't part of the containers library of the STL (containers being all the stuff here: https://en.cppreference.com/w/cpp/container ). I agree std::function is fine, it even has a pretty reasonable small-size optimization.
That's not even true for boost, no matter if they always advertise that. The lib is also notorious for bad decomposability (using only a subset without installing the whole monster). Not to speak about idiosyncratic naming and build system, making it sometimes hard to include it in meta builds of other libraries and frameworks.
In sum: Anyone sensible, regarding different kinds of footprint and dependencies will think twice, before pulling in these kind of libraries.
Having said that I think using abseil's containers is reasonable, even as a default, if you can afford the dependency.
> std::unordered_map
AFAIK unordered_map is the most awful of all standard containers.
I want my OWL, VCL back, not an hash table able to do lookups in micro-seconds
The point I was trying to make, was that from productivity point of view, there are more relevant stuff to fix in C++ than algorithm complexity of STL implementations.
Like catching up with what Java 5 standard library offers for networking and parallel/concurrent programming.
If you care about performance then it's not. (And if you don't care about performance then why are you using C++?) The standard requires that `insert` will not invalidate iterators, which basically forces everyone to implement `std::map` as a red-black tree, and those are pretty bad performance-wise on modern hardware mostly due to cache misses.
> If you need fast O(1) look up std::unordered_map is really not fit for purpose and requires you to come up with an hash function.
Modern hash table implementations (along with a modern hash function) are exactly what you should use if you need fast average-case O(1) lookup, so I'm confused why would you say that it's not fit for purpose? Unless you specifically meant only `std::unordered_map` which, yes, is pretty atrocious performance-wise (again, due to the iterator invalidation requirements).
Boost is better thought as a loose collection of libraries that try to follow some common design principles instead of a single monolithic library.
I can't defend the build system though.
App installation is a one time cost anyways. Did you mean s/download/startup/?
Being a polyglot developer, with Java, .NET and C++ as my favourite stacks, means I don't suffer from Java hate from C++ point of view, rather enjoy how one can combine their strengths to achieve a good outcome.
No it isn't and no it's not. There are even platforms where an STL isn't even provided out of the box, you have to pick one. And there's quite a few at that - libc++, libstdc++, stlport, etc...
But clang, g++, etc... they don't care. To them it's just another library you're linking against, no different from any other dependency. They don't provide it, they don't care. It can even be quite a pain in the ass to use the "native" STL of a given compiler, like trying to use libc++ with Clang on most Linux distros.
As having multiple implementations to choose from, that is the beauty of language standards.
Abseil and boost do not fall under that umbrella, and I belong to the C++ subculture that never ever touched them, or plans to.
eg. to use an 'int' you just declare one and use it. To use strings, you need to include <string.h>.
Now it's the Standard Library like in any other language.
java.util.Vector is standard as well but you'd be laughed out of a code review if you tried to use it anywhere. Similarly std::auto_ptr is in the standard, and is universally agreed to be trash to avoid like the plague. So much so it was (eventually) removed. The container section of the library has just sadly not had the same deprecation & removal of bad code put into it.
The claim was "STL containers are the sane default" not that "STL containers are more available". I stand by that claim being wrong. You have so far not actually attempted to counter it on any technical grounds, just bad appeal to authority fallacies.
Likewise std::auto_ptr got replaced by std::unique_ptr.
As you see the standard library keeps the knowledgable developers covered, no need to look elsewhere.
You are indeed wrong.