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Stroustrup on the Future of C++

/ASCII writes "Bjarne Stroustrup, the father of C++, has written an essay [PDF] on the features of the upcoming C++0x standard. In his essay, he argues that new features should whenever possible go into the standard library and not into the language, but that the language needs to shave of a few rough corners to make it easier to use for novices."

11 of 661 comments (clear)

  1. Dynamics in programming languages by jurt1235 · · Score: 5, Insightful

    It is interesting to see how an abstract language like a programming language evolves through time. I would think that in a language like C++ the more userfriendlyness should be in the libraries and not in the language, so I agree with the author on this point. Putting it in the libraries makes it better backwards compatible, and distributable.

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    My wife's sketchblog Blob[p]: Gastrono-me
  2. a 'few' rough edges by leomekenkamp · · Score: 4, Insightful

    Shaving off a 'few' rough edges to make it more easy for newbies... It's that what Sun tried to do? (hint: java)

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    Wenn ist das Nunstueck git und Slotermeyer? Ja! Beiherhund das Oder die Flipperwaldt gersput.
    1. Re:a 'few' rough edges by leomekenkamp · · Score: 4, Insightful

      Yes, I know these are fundamental changes, that's why I put the word 'few' in between quotes.

      Point of fact stays however: c++ has an enormous learning curve. Complexity in the language is imho comparable to Latin: you can almost recognise the author by lookin at the code. That complexity is far, far less in java.

      Especially the gc makes life a lot easier for even seasoned programmers.

      And by the way: you can be almost as un-OO in java as you can be in c++. Introspection in java is mostly used in 'frameworks', like for instance the serialization API; normally you almost never use it.

      --
      Wenn ist das Nunstueck git und Slotermeyer? Ja! Beiherhund das Oder die Flipperwaldt gersput.
    2. Re:a 'few' rough edges by orthogonal · · Score: 4, Insightful

      Shaving off a 'few' rough edges to make it more easy for newbies... It's that what Sun tried to do? (hint: java)

      Java's ok, but a few mistakes were made. Among the worst: over-reliance on the instanceof operator, and the need for something called a MethodNotSupported exception.

      Now think about what MethodNotSupported means in the context of Barbara Liskov's Substitution Principle:

      We've got a language that supports inheritance. Inheritance makes sense only insofar as Liskov's Principle is followed. Put simply, if class D inherits from class B, any "promises" that B made -- it's interface, both syntactically, in terms of public member names, and semantically, that the member functions really do do some particular thing -- any of those promises must also be kept by D, because we are saying, as Liskov tells us, that D is-a B.

      If I hand you an instance of D, and you plug it in place of am instance of B, anything that the B instance does, the D instance must at least do. Otherwise, how can you safely and with confidence substitute a the D in where the B used to be?

      But along comes Java, and the MethodNotSupported exception -- a method used by some of Java's core library, including, dismayingly enough, commonly used container classes. It's used so that a derived class can suddenly and at run-time throw it, telling you, "Whoops! Ha ha! Trickled you, I can't in fact really do what B promises! I claim I'm a B, but really, I'm not!"

      Now imagine you had a component stereo, and you replaced your tuner with a "better" tuner with all the same jacks as the original. You'd plug it in and expect it to do the same work as the original tuner, just with better reception or fidelity or whatever. Now what if you plugged in the new tuner to the old connections, and suddenly its display read: "Sure, I have a two-plug RCA input, but it's not actually connected to anything, so you can plug in an RCA jack but no sound will come out". That's what having a method that throws MethodNotSupport is like: the jack -- or member function name -- is there, but the implementation is not.

      D inherits ("extends") B, it says so right there on the label, but no sound comes out. With Liskov undermined, you don't really have an object oriented language at all. You don't really have true inheritance. What you have is a sham, a sham that can break down on you at run-time because an object is lying to you.

      And the upshot is that you don't see enough real object oriented programming by client Java coders. If the core library can get it that wrong, why should clients of that library bother to adhere to a standard?

      So you get lots of java code that does RTTI using instanceof and if( p instanceof Foo ) ... else if( p instanceof Bar ) ladders rather than calling p.virtualFunction(). Because coders won't take seriously OO that the language and its core libraries don't take seriously.

  3. A better wheel by Anonymous Coward · · Score: 5, Insightful

    Am I the only one who wonders why we need a successor to C or C++?

    I've sat through the past 10 years and watched things like Java and D and Objective C come, but meanwhile most serious OS level and game development continues to be in C or C++. Doesn't this demonstrate that new language are merely a distraction to developers who haven't fully exploited the current set?

    1. Re:A better wheel by onnel · · Score: 5, Insightful

      No, it's more a signifier that different problems need different solutions. If all you have is a hammer, everything may look like a nail, but if you know c++, perl, php, java and a few others, your toolbox will contain an appropriate solution for a broad range of problems. I write my games in c++, my websites in php and my text parsing utilities in php. Java and python also serve their niches. Anyone who believes that a single language is the best solution to all of the broad range of problems faced by programmers is sorely mistaken. Onnel

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  4. What we need is "Smoothed out" people... by brockbr · · Score: 5, Insightful

    Every time a cost of entry is reduced and the expected prerequisites are thrown aside, the result is a truly less capable *person*, not a more capable tool.

    Agreed - There are some things that need smoothing, but I for one am tired of dealing with people who lack a fundamental understanding of the *systems* as a whole. Examples of this are the folks coming out with CS degrees who aren't even capable of following a thought, let alone starting an actual career designing and developing software.

    For them, a tool like Java offers an entry level that is acceptable given there current capabilities - A tool geared towards THAT user (and a fine one at that).

    But C (and C++) can be leveraged by people who know the tool and *use* the tool for what it can do, even with it's high(er, intellectually) cost of entry.

  5. Syntactic candy. by mcc · · Score: 5, Insightful
    This is mere unnecessary conveniences. What exactly are they giving us here? Well, if I'm reading this right, "C++0x"* will give us:
    • Some cases where you can type ; where previously {} was necessary, saving as many as two keystrokes.
    • The lexer ambiguity where a<b<c>> and a<b<c> > meant entirely different things is fixed, saving as many as one keystroke.
    • EVEN MORE "free" constructors which may or may not work quite the way you wanted them to in practice.
    • More "fancy cast" operators, which sounds nice until you remember that if there's ever a time you find yourself using the C++ "fancy cast" operators, then there is a damn good chance that it's because you're doing something unwise enough it really would be a better idea to refactor the code to make the "fancy cast" unnecessary.
    ...in the meantime the fundamental issues with C++ remain not only unresolved, but unaddressed. The template system is still not a generics system, but an ugly cut & paste macro system which can incidentally be used for generics, with some caveats. The class system is still fundamentally brittle and unfriendly to simple things such as upgrading a DLL or determining at runtime if two objects are of the same type. The syntax is still a forest of features whose features interact in ways so crazy and unpredictable it approaches Perl in its chaos; references are still gimped; the distinctions in behavior and use between static and dynamic objects remain awkward and newbie-unfriendly. The features that people obviously desire to have in the language as demonstrated by their tendency to hack them in with third-party libraries (like BOOST) are-- they tell us-- a good thing, and they tell us we should continue to hack them in with libraries (like BOOST). That's nice. You know, that would be a lot easier though if we had a macro system** capable of anything smarter than blind code cut and paste-- or at least a macro system** fundamentally designed to be used for anything at all other than generics.

    Meanwhile, it appears if I'm reading this right that the most important differences in C++0x will be changes to the standard library. Great. The STL was defined how many years ago, and it's only just in the last few years that compliant implementations have become commonplace? How many decades will it be before the "C++0x" library changes have become common in a cross-platform compatible way?

    C++ is an extremely useful language, and making an update to C++ which changes as little as possible so as to follow some kind of "if it aint broken don't fix it" principle is an idea which makes a whole lot of sense. However it seems likely to me from reading this that C++0x will offer so little significant difference from C++ as to make itself simply redundant.

    * ("C++0x". Were they specifically trying to come up with a name less convenient than "C#"? Ah well, I guess we can call it "COX" or "cocks" for short.)
    ** "Template system"
  6. Re:wait a moment... by Kurt+Granroth · · Score: 4, Insightful
    Not when it's God talking

    Speaking of which, did anybody else notice the author description in that article?

    "Bjarne Stroustrup is the College of Engineering Professor in Computer Science at Texas A&M University"

    What!? Isn't that like saying the George Bush is a businessman from Texas? It's technically true, but completely misses the point on what matters.

    This makes even less sense when you try to find the target audience. If the person reading the article already knows who Bjarne is (by which I mean every single C++ programmer), then I could see them omitting the entire "creator of C++" description because, well, they already know... but then why have a description at all?

    If the person doesn't already know who this "Bjarne" is and they are reading the article, don't you think they'd want to know that he created the thing and therefore might have some relevant opinions on that matter?

    Very odd...

  7. Strostrup is in denial by Animats · · Score: 4, Insightful
    C++ is in deep trouble, and Strostrup is in denial about it.

    C++ is the only major language with extensive abstraction but without memory safety. All other major languages are either memory-safe or don't hide the underlying machinery. (Java, C#, VB, Perl, Python, etc. all have automatic memory management. Some use garbage collection; some use reference counts. C is unsafe, but hides nothing.) This fact is responsible for millions of program crashes every day. Most security holes in C++ code come from this problem. Java and C# were invented primarily to eliminate the safety problems of C++. The open source community has generally stayed with C, where at least you can see by examination what's going on. C++ is losing market share to Java.

    And Strostrup denies this is a problem.

    This has happened before. Last time, it was Wirth. Wirth designed Pascal, Modula, and Modula II, but refused to admit that each had serious problems. He fought external compilation in Pascal. He fought extensions to the language. He even fought compile-time arithmetic. In the end, he took Pascal from a major language to a historical footnote.

    Serious systems programming was once done in Pascal, but not in Wirth's version of it. The original Macintosh and Lisa software was written in nonstandard versions of Pascal. And much of the DOS era was built on Turbo Pascal. But proliferating nonstandard versions of Pascal caused another set of problems.

    C++ has been in decline for years. "Evans Data has found that the percentage of developers using C++ has steadily declined over the last six years--from 76 percent in the spring 1998 to 46 percent in fall 2004." Strostrup also denies that.

    The C++ committee has been taken over by template fanatics. Most of the committee's effort revolves around obscure template features that few will use, and which no responsible programming manager would allow on a mission-critical project. There's very little interest in language safety, and a vocal minority that insists language safety is undesirable or impossible.

    All is not well in the C++ world. Claming otherwise is irresponsible.

  8. It's far too late by pammon · · Score: 4, Insightful
    "If you think C++ is not overly complicated, just what is a protected abstract virtual base pure virtual private destructor and when was the last time you needed one?" -Tom Cargill

    The largest problem with C++ is its complexity. It is not just too complicated, it is *unmanageably complicated.* Some of the symptoms are:

    • The STL has inexplicable omissions. For example, there's no portable way to seed the built-in PRNG in the random_shuffle algorithm, rendering it useless.
    • Guruhood isn't good enough. Consider the seemingly simple task of creating a stack that works correctly with exceptions. It's extraordinarily difficult even for a guru.
    • Language features interact in nonintuitive ways, producing a combinatorial explosion. For example, if you overload a function in a class, you don't have to use the scope resolution operator, and if you override a function, you don't have to use it either - but if you do both, you DO have to use the scope resolution operator or else you get a compile error!
    Insofar as the new C++ standard adds stuff, instead of simplifying, this will only get worse. Since it's unreasonable to expect a new standard to remove features, the problem is unfixable. The result will be that programmers carve out their separate comfort zones, compiler vendors will not implement all features, and the monolithic C++ language will fragment into a Venn diagram of sublanguages. More so than today.