typeof()

[Jacob Carlborg]

On 2011-10-24 15:49, Steven Schveighoffer wrote:
> On Sat, 22 Oct 2011 08:00:50 -0400, Jacob Carlborg <doob at me.com> wrote:
>
>> On 2011-10-21 17:19, Steven Schveighoffer wrote:
>>> On Fri, 21 Oct 2011 10:54:47 -0400, Jacob Carlborg <doob at me.com> wrote:
>>>
>>>> On 2011-10-21 16:17, Steven Schveighoffer wrote:
>>>
>>>>> This can still be done. If you have the compile-time type you can
>>>>> always
>>>>> forcefully generate the run time info (I would expect such a feature
>>>>> when RTTI is fully developed).
>>>>
>>>> The thing is that you may not have access to the compile-time type,
>>>> i.e. :
>>>>
>>>> class Base {}
>>>> class Sub : Base {}
>>>>
>>>> Base sub = new Sub;
>>>>
>>>> Now the compile-time information specific for Sub is gone when
>>>> accessing "sub".
>>>>
>>>> I have this problem with my serialization library. To workaround this
>>>> the user have to register the compile-time type with the serializer to
>>>> be able to (de)serialize via base class references.
>>>
>>> Well, .NET requires you to put an attribute on a class to allow it to be
>>> serializable. And that doesn't seem to get in the way of .NET code that
>>> uses serialization.
>>>
>>> -Steve
>>
>> If I can make it work without specifying an attribute on a class why
>> shouldn't I. One thing less to think about. It's just in this special
>> case the type needs to registered with the serializer.
>
> Serialization requires metadata about the datatypes being serialized. If
> I don't want to serialize something, why should I have to pay the bloat
> cost of being *able to* when I never actually do?

I don't have a good answer. In some cases one wants to have runtime 
reflection and in other cases that just causes bloat.

BTW, in general, serialization doesn't not require metadata, only when 
serializing through base class references.

> I don't mind registering data types with the serializer that need to be
> serialized. I know it would be nicer from a serializer library writer's
> perspective to just say everything is serializable, but I'd rather have
> D be efficient when it needs to be instead of trying to support every
> possible use case no matter how uncommon. Again, when I serialize
> things, I typically am in control of those data types. I have not yet
> had a case where an *opaque* data type that needed to be serialized
> wasn't one that I wrote myself.
>
> And I wrote an entire system in C# that used remoting exclusively for
> client-server communication. Every data type that needed to be used for
> remoting must be serializable.
>
> -Steve


-- 
/Jacob Carlborg