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Why ESR Hates C++, Respects Java, and Thinks Go (But Not Rust) Will Replace C (ibiblio.org)
Open source guru Eric S. Raymond followed up his post on alternatives to C by explaining why he won't touch C++ any more, calling the story "a launch point for a disquisition on the economics of computer-language design, why some truly unfortunate choices got made and baked into our infrastructure, and how we're probably going to fix them."
My problem with [C++] is that it piles complexity on complexity upon chrome upon gingerbread in an attempt to address problems that cannot actually be solved because the foundational abstractions are leaky. It's all very well to say "well, don't do that" about things like bare pointers, and for small-scale single-developer projects (like my eqn upgrade) it is realistic to expect the discipline can be enforced. Not so on projects with larger scale or multiple devs at varying skill levels (the case I normally deal with)... C is flawed, but it does have one immensely valuable property that C++ didn't keep -- if you can mentally model the hardware it's running on, you can easily see all the way down. If C++ had actually eliminated C's flaws (that is, been type-safe and memory-safe) giving away that transparency might be a trade worth making. As it is, nope.
He calls Java a better attempt at fixing C's leaky abstractions, but believes it "left a huge hole in the options for systems programming that wouldn't be properly addressed for another 15 years, until Rust and Go." He delves into a history of programming languages, touching on Lisp, Python, and programmer-centric languages (versus machine-centric languages), identifying one of the biggest differentiators as "the presence or absence of automatic memory management." Falling machine-resource costs led to the rise of scripting languages and Node.js, but Raymond still sees Rust and Go as a response to the increasing scale of projects.
Eventually we will have garbage collection techniques with low enough latency overhead to be usable in kernels and low-level firmware, and those will ship in language implementations. Those are the languages that will truly end C's long reign. There are broad hints in the working papers from the Go development group that they're headed in this direction... Sorry, Rustaceans -- you've got a plausible future in kernels and deep firmware, but too many strikes against you to beat Go over most of C's range. No garbage collection, plus Rust is a harder transition from C because of the borrow checker, plus the standardized part of the API is still seriously incomplete (where's my select(2), again?).
The only consolation you get, if it is one, is that the C++ fans are screwed worse than you are. At least Rust has a real prospect of dramatically lowering downstream defect rates relative to C anywhere it's not crowded out by Go; C++ doesn't have that.
He calls Java a better attempt at fixing C's leaky abstractions, but believes it "left a huge hole in the options for systems programming that wouldn't be properly addressed for another 15 years, until Rust and Go." He delves into a history of programming languages, touching on Lisp, Python, and programmer-centric languages (versus machine-centric languages), identifying one of the biggest differentiators as "the presence or absence of automatic memory management." Falling machine-resource costs led to the rise of scripting languages and Node.js, but Raymond still sees Rust and Go as a response to the increasing scale of projects.
Eventually we will have garbage collection techniques with low enough latency overhead to be usable in kernels and low-level firmware, and those will ship in language implementations. Those are the languages that will truly end C's long reign. There are broad hints in the working papers from the Go development group that they're headed in this direction... Sorry, Rustaceans -- you've got a plausible future in kernels and deep firmware, but too many strikes against you to beat Go over most of C's range. No garbage collection, plus Rust is a harder transition from C because of the borrow checker, plus the standardized part of the API is still seriously incomplete (where's my select(2), again?).
The only consolation you get, if it is one, is that the C++ fans are screwed worse than you are. At least Rust has a real prospect of dramatically lowering downstream defect rates relative to C anywhere it's not crowded out by Go; C++ doesn't have that.
He seems to think he has some great insight into why C is C, why C++ is C++. But really, he is so fucking clueless I don't know where to start.
There's enough business logic programmed in C++ and Java to keep both languages around until my kids retire and they're not yet in the workforce. Rust and Go, yeah doubt there's a single company of any size running their business processes on either.
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
He's a person, not a technical description.
We have enough abbreviations in tech.
Hate it when people do that.
Thank you, Bradley Manning, Edward Snowden and so many others, for courageously defending humanity, my freedom and more!
The higher the level of abstraction in your language, the higher the overhead it will create. Now, it needn't be so absolutely stupidly overengineered as .net is, but still the metric fits, the more safeguards and handrails your language comes with, the higher the overhead it incurs to have them. This is admittedly not really a huge problem in today's working environment because our computer speeds are far greater than our needs.
Still, somehow it feels silly that I need increasingly more powerful computers just to run the same kind of program, only because programmers can't be assed to learn their trade and instead rely on ridiculously overblown frameworks that is the equivalent of delivering a pack of soda with a semi because you have to bring a soda factory along with the workforce since the framework doesn't know how to deliver a single soda.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
The reason we have to say "don't do that" is because C++ remains compatible with C and older version of C++. There are literally billions of lines of existing C++ code out there, and the language committee realizes it can't just snap its finger and order everyone to rewrite all that old code (which is stable, functional, and debugged, btw) because we have something newer and better now.
It's pretty straightforward to write safe, new C++ code if you understand how to use the new features and abstractions. I wrote an entire game / game engine recently using modern C++, and it's amazing how few bugs I've had thanks to recent language improvements and techniques.
I'm not sure where this "large projects can't enforce code discipline" idea comes from. What does he think "coding standards" are, which nearly every major company, organization, or project has? And if someone doesn't understand how to use a smart pointer instead of a raw pointer or avoiding class inheritance hell at this point, then really, they shouldn't be contributing to your C++ projects.
I get it that some people dislike or distrust C++. It's a complex language that's hard to master. They don't like that it makes a lot of compromises in the name of practicality, but that real-world practicality is why many of us use it for large, performance-critical real-world projects. I'd never argue that C++ is the right language for every project. In fact, it's a fairly specialized language at this point. But that level of hyperbole is a bit annoying.
Irony: Agile development has too much intertia to be abandoned now.
Arguing that it's harder for large-scale projects to manage a 'well, don't do that' approach implies that he's completely missed the last 40 years of tool development. This is much more of a problem for small C++ projects than large ones. Large ones have pre-push hooks that run static checkers that enforce rules like no bare pointer and no operator new / delete. It's the smaller ones that rely on programmer discipline to do this that are more likely to have problems.
Go is a horrible language. It has multithreading as a core part of the language, but no memory model and no type system that can express notions of sharing or immutability. The designers clearly realised that generic types are important, and so added precisely one to the language (the map type, which is parameterised on the key/value types). It has a map type that maps from one object type to another, but no way for users to define what equality (or ordered comparison or hash) means on objects.
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The big problem when it comes to using anything other than Fortran, C or C++ is that 20 years after the first MMX and SSE instruction sets have been added to CPUs, there are only a handful of compilers that known how to vectorize even loops that are hand-crafted to be vectorizable - and the ones that can do it are all commercially licenced (GCC might theoretically have some support for it, but in reality it doesn't vectorize most things). And since most of the performance advancement in silicon has for a long time now been focused in SIMD units, that means that for any performance sensitive workload there are no feasible alternatives. If it has taken GCC 20 years to get not very far, how long will be be before much younger compilers get anywhere with this performance critical feature?
Take the low-level access provided by C, and then add the ability to construct both compile-time and run-time abstractions to an incredibly high level, but with as little cost as possible. That's C++.
C++ is an amazing achievement.
Every academic language approaches Lisp, but every practical language (you know, the ones that actually make the world turn) approaches C++; Bjarne said as much, and he was right.
Anything that allows us to reduce errors, increase functional complexity, reduce development time, improve readability and maintainability, and/or make it easier to code for a greater amount of people, is progress in my book. Working at a higher abstraction level achieves some or all of those goals.
And good frameworks help with that. When I build a house, I don't want a craftsman who takes time to learn how to use an adze so he can plane down lumber to the correct size for the job; I want a builder who knows he can get lumber of the correct dimensions right at the store. The skills to build instead of buy are useful in many trades (both building and programming), but they are expensive and a possible source of additional errors. Frameworks are often a good answer to that... as long as the developer understands the nature of the framework, its limitations, the licensing model, its viability, and thus can assess the consequences of using it.
If construction was anything like programming, an incorrectly fitted lock would bring down the entire building...
What I find kind of annoying is that Ada fixed all these flaws decades ago with Ada 95, now it is at Ada 2012 and still gets no love, just because it's a bit more verbose than C if you use it correctly. (Though not necessarily more verbose than C++.) Sure it has some flaws, e.g. concerning aliases and their scoping rules, but these are mostly inconveniences and some of them have been fixed in Ada 2012. But it doesn't stop there, the same story can be said about dynamic languages. Take fancy new dynamic language X and you can be fairly certain that CommonLisp solved all the problems of the new language already in the 80s.
Maybe developers are in the end less rational than they think? It seems to me that a language must have serious flaws, lots of incoherent shortcuts and tricks, or at least a cryptic syntax to become really successful.
Usually, when you try to merge the 2 ideas, you end up with something as stupidly inefficient as run-time introspection.
So, because the guiding principle of C++ is "zero-overhead abstraction", perhaps it is the case that you must explicitly choose where the computation will occur—run-time or compile-time.
I remember I interacted with him back when he started the irker project.
That pretty trivial piece of software, written in Python, was riddled with bugs, and no amount of bug reporting and discussing with him the design mistakes got anything fixed for a whole week, despite him actively trying.
I rewrote the whole thing in C++ in two days and it always worked robustly from the get go.
Personally, I think way more problems arise of terse syntax and high symbolic abstraction that C/C++ and derived languages like so much. I mean, I'm as lazy as the next programmer and that's why I like C (and its derived languages) but even I cannot ignore that
{ (a!=1)?b=!b:b=0}
is way less readable than
begin
if a is not equal 1 then set b equal complement of b else set b equal 0
end
You'd immediately spot an error in the second because the sentence would look "wrong".
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
If GC is the reason for 6 GB smartphones, why does booting your non-GC'd Windows desktop take more memory than booting a GC'd Lisp Machine OS?
Ezekiel 23:20
It's not always so clear cut. What you say is definitely true for naive compilers, but higher-level abstraction also often mean more information for the compiler and more freedom for the compiler. These can translate to better optimisations. To give a trivial example, languages like Java provide an abstraction that looks like a C struct, but don't require that the memory layout be visible to the programmer. Imagine that you create a struct-like Java object with RGB values to represent a colour and you do the same in C. Now you put them in an array and try to do some processing on them. The C version is constrained to lay out the objects as three fields with no padding (this is visible in the language with sizeof and will break ABIs if it dynamically changes). The Java version, in contrast, is allowed to put an unused padding field at the end of the struct. Why does that matter? If you want to vectorise the loop, then being able to guarantee 4-element alignment for every object in the array is a huge win. This is a legal transform for a Java compiler, but not a legal transform for a C compiler unless it can prove that no pointers to the array escape (and a few other constraints).
The big advantage of C was that a fairly simple compiler for a simple architecture could get very good performance. The disadvantage for C is that compilers quickly hit diminishing returns and the abstract machine makes a number of desirable optimisations unsound.
For example, if your language has a first-class notion of immutability, then this gives the compiler the opportunity to elide copies or add copies if they make sense for NUMA systems, and gives the compiler a lot more freedom with regard to reordering or eliding loads. Similarly, if your source language has higher-level notions of sharing then this means that you can avoid a lot of defensive memory barriers that you'd need for correct C/C++ code. If your language has stricter guarantees on aliasing, then a whole lot of optimisations suddenly become easier.
Any compiler optimisation is a mixture of two things: an analysis and a transformation. The analysis must be able to tell you if the preconditions for the transform are met. The more information you can give to the compiler, the more often the analysis can prove that the preconditions hold and enable the transform.
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And good frameworks help with that. When I build a house, I don't want a craftsman who takes time to learn how to use an adze so he can plane down lumber to the correct size for the job; I want a builder who knows he can get lumber of the correct dimensions right at the store.
On the other hand, when all you want to build is a garden shed, you can do it yourself in a quick week-end afternoon project by quickly nailing a few planks together. You definitely don't want a several month-long adventure involving half a dozen sub-contractors (and each further down, their own individual group of a dozen of sub-contractors), plus hiring a few special planification manager (because sub-contracors D and Y each out-source their screw to a different sub-sub-contractor. Incompatiubles) which will all require two hectars of work space around your shed. And somehow the garden shed need to be connected to an industrial triphase 380V power connector in order to be able to function.
Some time, over reliance on frameworks and helpers means that some very simple projects that would be handled by a few dozens of C or C++ lines of code (perhaps a couple of hundreds top), suddenly need to pull more than 20 MiBs of libraries in the package and are dependent on 200 different github repositories (hoping that they'll not blocked on the dev's whim - see Node.js and string alignement). And you need to use special command line settings to tell the VM to allocate 2 GiB of memory for the process.
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The higher the level of abstraction in your language, the higher the overhead it will create.
This is exactly why C++ remains popular among those who create large, complex, high-performance applications. C++ is well known for using zero-cost abstractions. That means you get the performance of low-level C code, but can design much safer interfaces and type safety in your code which allow the compiler, not a runtime, to validate that the code is correct and safe.
For certain types of applications, it's an effective compromise between the pragmatism of retaining backwards compatibility with decades-old ecosystems, while at the same time providing better safety and abstractions than C.
Irony: Agile development has too much intertia to be abandoned now.
With some extra spaces, and the whole thing changed to an expression (which is how ?: is supposed to be used) it's a lot easier to read.
b = (a != 1) ? !b : 0
The advantage of the ternary operator is that you only need the LHS part once, which helps if it's a more complex variable.
Pimpl is solvable by creating an implementation class and and interface class that has a reference to that class, and if you are crying about memory safety starting with C++ 11 there are smart pointers.
Guns don't kill people; Physics kills people! - John Lithgow as Dick Solomon on Third Rock From The Sun
How do I write drivers and firmware in Go? I think C is going to be around for awhile.
We'll make great pets
But what happens when everybody buys lumber at the store? There still must be somebody that make sure the lumber is the right size and quality for your project. This problem is exactly why we today need giga range cpu's and ram just to watch a web page. Nobody knows how to deal with the details any longer, and so they end up building a new house every time there is a new problem.
If your point was to make that part more readable, I think I want you on the other team in the next debate.
If you find that unreadable, I don't want you on my team in the next software project.
Well, I do have to say that the code would not pass my code review. Not because of the use of the ternary operator, because of the meaningless variable names. I'd also ask that "0" be replaced with "false".
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For HPC (high performance computing) I don't see C++ going anywhere. For HPC the only viable languages I see are C, C++ and Fortran since they have the best optimizing compilers.
Mostly I use python for command and control with a simulator written in C++ and this seems to be a pretty common setup for HPC applications.Command and control often has a lot of code but is 1% of the compute time so write it in a high level language and then do the simulator is something that is FAST.
Computer modeling for biotech drug manufacturing is HARD!
A colleague and I were joking around one day, when a hardcore-dev (with a lot less humour, and chronic flatulence, as I remember) overheard us. He maintained that super-terse code is easier to read than the alternative. Since we were just messing about, we both just let him say his peace and then stated that the One True Language was of course Turbo Pascal 6 (which sort of ended the conversation).
My take on it is that the terse syntax does make sense (more quickly) to someone who knows the syntax really well. If you don't know it quite as well, then the long-form is better because as OP says "the sentence would look wrong". Also, actual words are 'googleable' where as it's hard to lookup the meaning of "~->" or whatever. Thus, the long-form plays to more average programmers.
The question then becomes... who should a language be for? For the super-expert, or for the midrange programmer, or possibly even the junior? IMHO, midrange is a good place to aim at because that's where the majority are, and if they're using your language then you'd want them to be able to do so reasonably easily and safely. That way, of all the billions of opcodes executed around the world as a result of your language, the majority of them will be reasonably safe and sensible.
A C compiler may add padding, but its ability to do so is constrained (or mandated) by the platform ABI. The layout of a struct is exposed directly in the language because you can ask for sizeof() the struct (which, if you subtract the size of all of the fields will tell you the total padding) and you cast a pointer to a field and a pointer to the struct to char*, subtract one from the other, and get the offset of each field. This means that it is effectively impossible for a C compiler to add padding to make optimisations easier (the only case in which they will reliably do it is for on-stack structs that are not address-taken).
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People who do electrical engineering learn to read and understand the funky symbols they use in electricity. We don't expect them to write out everything in plain English. It's the same with programming. Your Pascal-y pseudo-code took how much more space and time to convey no extra information? Your pseudo-code actually took longer for me to parse and understand than the C version.
GC was hacked-on for decades to no avail (in bringing it low-level).But now here it works well (very fast, concurrent).
What changed? The language spec was made very simple.
Compiling was a very tricky, slow business. Now here it's fast and relatively simple.
What changed? A simpler language. Smart people who know which options to take away.
Only painfully low-level languages could work with raw memory pointers. Now we have that in 2 friendly, "default-safe" languages.
What changed? Realization a lot of power comes from low-level operations.
So C & it's layered C++ will break as safer variants with the same power begin to exist.
High level languages depended on dozens of C libraries and libc. Go needs none of those.
What changed? A realization this is important.
A fork of Go now runs without a kernel on bare-metal ARM. That's the right space to grow into a kernel-module-capable language. Languages aren't fast or slow, their implementations are. Go's ease of portage suggests it could show up in the kernel.
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