[lldb-dev] Unifying ctor+Clear() inits into in-class initializers?

[Leonard Mosescu via lldb-dev]

>
>         void Clear() {
>           this->~ClassName();
>           new (this) ClassName();
>         }


My 2c: this is clever, but not without downsides:
1. It may do more than intended (it will destroy all members / bases)
2. It forces construction and 'reset' to be exactly the same, which is not
always desirable
3. Most importantly if you really want a freshly initialized object, just
do that (create a new object)

I like in-class initializers, but for clear/reset operations I prefer a
standalone operation. And as Pavel suggested, calling 'clear' from the
constructor is a good way to factor out commonality.



On Sun, Nov 19, 2017 at 6:58 AM, Jan Kratochvil via lldb-dev <
lldb-dev at lists.llvm.org> wrote:

> Hi,
>
> https://reviews.llvm.org/D40212
>
> At least DWARFCompileUnit and I see even for example MachVMRegion duplicate
> intialization of fields in both their constructor and Clear().  Moreover
> the
> initialization is in different place than declaration of the member
> variable.
>
> Is it OK to just use in-class member variable initializers and:
>         void Clear() {
>           this->~ClassName();
>           new (this) ClassName();
>         }
> ?
>
> Pavel Labath otherwise suggests to just call Clear() from the constructor.
> Still then I find the code could be more readable with in-class members
> initializers - moreover during further refactorizations+extensions.
>
>
> Thanks,
> Jan Kratochvil
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