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digitalmars.D - Class member variable initialization vs. C++ initializer lists, and

A discussion came up on Reddit about C++'s initializer lists, and 
I realized I didn't really know what other languages in the same 
space do for member initialization. I'm not looking to start a 
language war here; I'm asking out of curiosity/general knowledge.

I found a prior discussion on what D does [1], and I think the 
most relevant part is this (reduced slightly from the original):

    class MyClass {
        int d = 6;
        this(int val) {
            d = val;

 You are correct that in the case of the [...] constructor,
 two assignments effectively take place, d = 6, then d = 7.
In C++ terms, I would describe this as "d is first initialized to 6, and then assigned to from 7". However, if that's the only mechanism for "initializing" a class variable it seems to me like this would cause problems with: * Classes that can't be default-initialized because they need some data to be provided not known until runtime and it is desired that there not be a way to construct an "empty" object; something like this C++: class Person { string name; // no Person() provided Person(string n) { n = name; } // not "idiomatic c++", but works }; class EmployeeRecord { Person person; // no this() provided EmployeeRecord(string name) : person(name) {} // no way to *not* use init-list }; * Classes that can't be assigned. I'm having a harder time coming up with a good example here that would usefully be a member of another class, but some RAII objects could fit the bill. (For example, std::lock_guard is not copyable or assignable.) How would these be handled in D? Do these concepts exist in some form? If so, how would you initialize them? Evan [1] https://forum.dlang.org/thread/jg9ajr$1iaq$1 digitalmars.com
May 10 2018