Reset all Members of a Aggregate Instance

[Jakob Ovrum via Digitalmars-d-learn]

On Thursday, 3 December 2015 at 21:04:00 UTC, Nordlöw wrote:
> Given
>
>     class C
>     {
>         // lots of members
>     }
>
> and a function
>
>     f(C c)
>     {
>     }
>
> is there a generic way, perhaps through reflection, to reset 
> (inside f) all members of `c` to their default values? 
> Something along
>
>     foreach(ref member; __traits(allMembers, c))
>     {
>         member = typeof(member).init;
>     }

import std.traits;

foreach(i, member; FieldNameTuple!C)
{
     alias FieldType = Fields!C[i];
     static if(isMutable!FieldType)
         __traits(getMember, c, member) = FieldType.init;
}

However, it doesn't work in the presence of private fields. A 
better alternative is probably to `destroy` the instance then 
`emplace` to default-construct a new instance over it.