Can you provide some feedback for this C++ idea /

Question

Can you provide some feedback for this C++ idea /

proposal?

Primary constructors for C++

Problem:
C++11 allows in-class member initialization. However, in-class initializers have no access to constructor parameters, which makes them useless in many scenarios. Example:
template<typename T, unsigned INIT>
class MyClass {
public:
MyClass(unsigned init) {}
private:
T x0 {INIT}; // OK
T x1 {init}; // Error
}
So essentially in this case C++ favors compile-time template interfaces over run-time constructor interfaces.

Possible solution: Primary constructors (similar to Scala, Kotlin and abandoned C# proposal)

We can designate one constructor as primary. Parameters of primary constructor should be visible to in-class initializers. All other constructors must call primary constructor in their constructor initialization list.

For example, we can use following syntax (similar to Scala/Kotlin):
template<typename T, unsigned INIT>
class MyClass (unsigned init) {
public:
// secondary ctor
MyClass() : MyClass(42) {}
private:
T x0 {INIT}; // OK
T x1 {init}; // OK
}

#c++ #embedded #programming #russian

0

25.09.2018

1 ответов

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Igor Akhmetov · Accepted Answer

Igor Akhmetov

Чем этот подход лучше чем самому написать primary constructor и в нем поля проинициализировать?

0

25.09.2018

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