Chances of D getting proper runtime reflection?

[Jacob Carlborg]

On 2011-08-22 02:43, Robert Jacques wrote:
> On Sun, 21 Aug 2011 11:20:14 -0400, Jacob Carlborg <doob at me.com> wrote:
>> On 2011-08-21 15:20, Robert Jacques wrote:
>>> On Sun, 21 Aug 2011 06:55:52 -0400, Jacob Carlborg <doob at me.com> wrote:
>>>
>>>> What are the chances of D getting proper runtime reflection? Something
>>>> like this:
>>>>
>>>> class Foo
>>>> {
>>>> private int a;
>>>>
>>>> private void bar (int i)
>>>> {
>>>> a = i;
>>>> }
>>>> }
>>>>
>>>> auto foo = new Foo;
>>>> Object o = foo;
>>>> o.setInstanceVariable("a", 3);
>>>> assert(foo.a == 3);
>>>>
>>>> This would be useful as well:
>>>>
>>>> o.send("bar", 5);
>>>> assert(foo.a == 5);
>>>> assert(foo.a == o.getInstanceVariable("a"));
>>>>
>>>> Currently I have most use of the first example. These example should
>>>> work regardless if the fields/methods are private, protected or public.
>>>>
>>>> As far as I know this wouldn't require any changes to the language,
>>>> only
>>>> the compiler and runtime would need to be modified. To me, it doesn't
>>>> look that complicated to implement, the runtime just needs to store an
>>>> associative arrays that maps names of instance variables and methods to
>>>> their addresses. This could probably be stored in the ClassInfo.
>>>> Something like this:
>>>>
>>>> Foo.classinfo.setInstanceVariable(foo, "a", 3);
>>>>
>>>> And this could be shorted to:
>>>>
>>>> o.setInstanceVariable("a", 3);
>>>>
>>>> "setInstanceVariable" could just forward the call to the class info.
>>>>
>>>
>>> I've basically done this entirely in library code: see
>>> https://jshare.johnshopkins.edu/rjacque2/public_html/variant.mht
>>
>> The whole point was to have direct support in the language/runtime so
>> these library solution were not needed. Does your solution work when the
>> static type is Object and the runtime type is a subclass?
>>
>
> Yes, so long as at some point the subclass is registered by variant,
> either manually or auto-magically via reflection on another type. The
> docs had an example of this:
>
> module example;
> class Grade { real mark; }
> class Student { Grade grade; }
> void main(string[] args) {
> Variant.__register!Student;
> Variant grade = Object.factory("example.Grade");
> grade.mark(96.6);
> assert(grade.mark == 96.6);
> }
>
> notice how Student had to be manually registered, but Grade was
> registered auto-magically.

I already have this in my serialization library, I want to avoid that. 
That was the whole point of my original post.

-- 
/Jacob Carlborg