DISCLAIMER: the following is a pure hypothetical list of wishes I had about C++. You should treat it as it is. This is not supposed to be a collection of community agreed list of wishes, nor it is intended to make complete sense, as some of these features are available through the standard library. Please procedure further with that in mind.
I was thinking lately what are the top language features I am missing from C++ but are available in other similar languages (such as C# or Java). After some consideration I have come up with the following list. Note that this list refers to language features only, and not library features and they are listed in a rather random order.
- Native string type, other than char*, rather a language built-in std::string
- Native datetime type, that would allow us to specify points of times without a built-in resolution. Obviously adding this after the chrono library makes no sense. This refers rather to a language feature that should have been available from the beginning. The reason for that is specifying date and time is a common operation we often need to do.
- Native interfaces, other than abstract classes with pure virtual functions only as it is currently possible, because such classes can also contain data members. The reason for this is convenience in defining interface. The syntax for this should not require us to define the member functions as virtual and pure, they should be virtual implicitly. Interface member functions should also be mandatory public so we should not have to declare that either. And last, but not lease, interfaces define contracts and therefore a special interface class should not allow to define data members, not static methods.
- Properties, basically a pair of get/set accessors over a data member. Having automatic properties to create data members and accessors would be even better. We manually write these all the time and having the compiler generate them for us would be a productivity boost.
- Extension methods that would enable extending exiting types with new methods without modifying the type itself. This can be be achieve in different ways, but support in the language for this feature means we can extend existing code with new methods without touching it, and call these methods as they were actual member of the class.
- Template type constraints basically what concepts will provide in the future, so I will not insist on this. Current workarounds with enable_if and SFINAE, static_assert and even deleted functions currently exist.
- Events to enable a subject to notify observers that something has happened. Obviously this can be implemented explicitly using existing functionality, having native support for that would simplify writing code and increase productivity.
- Switching on other types than integral types, especially on strings. In general it should be possible to switch on any compile time constant expression. The reason for this is to replace if-else statements with a simpler to write and read switch statement.
- Finally block for a try-catch so we can specify code that should execute regardless of whether an exception occurs or not. This is supposed be achieved by implementing the RAII idiom. Resources should be released properly upon destruction, but the reality is that a lot of code does not use RAII. Having finally blocks would enable us to run clean up code either if an exception occurred or not.
- Static classes, that can contain only static members, and static constructors, that are called before main and have access only to static members of a class (there is actually a proposal for static constructors under discussion for standardization). Helper functions may be implemented as static members of a class, and having the class as static would be a constraint on the class to only contain static members.
I do known and understand the principles of C++ and I know these may look counter intuitive. I know why string is a library container, and why time points are available through a library and why these are general purpose implementations intended to meet many needs. For instance the chrono library is resolution agnostic, which means that in the future clocks will deliver picosecond resolution we won’t need to update the library to benefit from that.
On the other hand the reality is that general purpose implementations lack many features developers use all the time, such as converting a string to upper or lower case. This is available in many languages or string libraries, but not in the standard library string. Yes, we can implement that simply in a helper function, but if extension methods were available we could call such a helper function as it was a member of the string class, which would look, arguably, more natural, and also similar to what is available in other languages.
Another reality is that many developers use more than just one language. Some of these features would enable developers coming from a background of .NET or Java development to get a faster and better grasp at C++.
The most important benefits of these feature would be less and probably more readable code and an increased productivity. There are workarounds for these and, yes, we can live without them. But I do not believe that makes at least some of them unreasonable.
I would like to hear what are the features that you miss the most and see if they also appear on this list.Hits for this post: 6178 .