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Closed 13 years ago.

While I am excited that C++0x will be much more fun to program in than C++98, I sometimes feel that some of the new features leave something important to be desired.
For e.g. initializer lists can not be deduced as references to arrays, variadic templates don t allow for member packs or arbitrary expression expansion, local classes can t be templates or contain templates or have in-class member initializers, lambdas can t be templates, constexpr can t help with compile time processing of string literals, user defined string literals can t be templates (whereas user defined number literals can be), decltype behaves significantly different in certain cases based on whether you parenthesize its operand or not (would have preferred a separate exprtype ).

I recognize that the standard s committee had to make some very difficult choices and compromises (since it really isn t meant to innovate, and because it has fairly limited resources), and I respect them deeply and am very grateful to them for doing what they do. This post isn t meant to denigrate their efforts (I am very much looking forward to using C++0x) - but to gauge how strongly others feel about some of these features.

With that in mind, I pose to you the following questions:

1) What are the new features that you are completely satisfied with?
2) What are the new features that you are partially satisfied with - and what would it take to make you more satisfied?
3) What are the new features that you wish had definitely not been added?

For a list of all the features, I will refer you to Stroustrup s List.

Thanks!

Answer 1

I m very annoyed by many things in C++0x. All of them from the same reason -- while the new features are absolutely brilliant, the need of backwards-compatibility makes many of them look like ugly hacks...

Example 1:

SequenceClass(std::initializer_list<int> list);

instead of

SequenceClass(int... list); // or other nice in-language way

Example 2:

class D [[base_check]] : public B {
    void sone_func1 [[override]] ();

instead of

class D : public B {
    override void sone_func1 ();

Example 3:

std::shared_ptr<Target> m_target;

instead of

Target ^ m_target;

... okay, that last one is my own happiness :>

Of course all of these are subjective -- many people prefer it otherwise. What annoys me is the fact that we have to keep backwards compatibility so the language can t fully evolve. This is ESPECIALLY annoying in cases of safety -- I d really like to see C-style casts go away...

I really hope that C++ will someday adapt a "deprecation" mechanism, akin to what Khronos did to OpenGL since 2.0.

Answer 2

It s good they have alignment and memory model and thread local stuff. That should have been in ten years ago and there s no reason it should have taken so long.

The delegating constructors is something I wanted forever, but the implementation is horrible. If that s the best they can do it should be removed.

Pretty much everything else is just added complication and yet more initializer list nonsense. Which is why it s impossible to make delegating constructors properly. They should be trying to simplify the language, not add yet more metaprogramming complexity that makes so many problems.

Answer 3

lambdas, auto, rvalue references
templated typedefs; I think the syntax is awkward, but I m glad they exist in some form
Concepts. Oh wait... I win

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