Serialization for D. Comments, please!

[Denis Koroskin]

On Wed, 27 May 2009 01:23:58 +0400, Bill Baxter <wbaxter at gmail.com> wrote:

> On Tue, May 26, 2009 at 12:19 PM, Denis Koroskin <2korden at gmail.com>  
> wrote:
>> On Tue, 26 May 2009 21:44:49 +0400, Bill Baxter <wbaxter at gmail.com>  
>> wrote:
>>
>>> On Tue, May 26, 2009 at 2:35 AM, Denis Koroskin <2korden at gmail.com>
>>> wrote:
>>>> On Tue, 26 May 2009 13:29:39 +0400, Qian Xu
>>>> <quian.xu at stud.tu-ilmenau.de>
>>>> wrote:
>>>>
>>>>> BCS wrote:
>>>>>
>>>>>> I'm planning on taking a crack at a Serialization template library  
>>>>>> and
>>>>>> I'm
>>>>>> looking for feed back. My thinking so far is up on my blog here:
>>>>>>
>>>>>>
>>>>>
>>>>> http://arrayboundserror.blogspot.com/2009/05/serialization-for-d-part-1-of-n.html
>>>>>>
>>>>>> Please comment! (here or there, doesn't matter, I think I'll see  
>>>>>> both)
>>>>>
>>>>> A question:
>>>>> Should every object contain "mixin Serializable!()" in its  
>>>>> declaration?
>>>>> It is easy to add this in own classes, but not easy to 3rd-party
>>>>> libraries.
>>>>> for instance: tango
>>>>>
>>>>>
>>>>> --Qian
>>>>>
>>>>
>>>> Good serialization library supports external serialization via  
>>>> template
>>>> specialization (or similar tricks) :)
>>>
>>> I'll also add that you should be able to properly
>>> serialize/deserialize a BaseClass pointer that actually points to a
>>> DerivedClass.
>>> This is pretty tricky to get working seamlessly when combined with the
>>> external serialization requirement.
>>> H3r3tic's xpose library has this working IIRC.
>>>
>>> --bb
>>
>> Sure! How about the following test:
>>
>> struct A
>> {
>>    mixin Serializable!();
>>
>>    B[] b;
>> }
>>
>> struct B
>> {
>>    mixin Serializable!();
>>
>>    A a;
>>    int i;
>> }
>>
>> B[] b = new B[1];
>> b[0].a.b = b;
>> b[0].i = 42;
>>
>> A* a = &b[0].a;
>>
>> data = serialize(a); // should serialize outer struct (B), too, because  
>> it is accessible through a
>>
>> a = deserialize(data);
>> assert(a.b.length == 1);
>> assert(a.b[0].i == 42);
>>
>> BTW, thanks for reminding about xpose. I gotta compare it,  
>> doost.serialize and mine own one against each other in terms of  
>> efficiency and size (for binary output) someday.
>
> That's not quite what I meant.
>
> I mean this:
>
> /// 3RD PARTY LIB
> class BaseClass
> {
>      string toString() { return "base"; }
> }
>
> class DerivedClass
> {
>      string toString() { return "derived"; }
> }
>
>
> /// MY CODE
>
> [...some kind of class registration here....]
>
> BaseClass b = new DerivedClass;
>
> data = serialize(b);
> b2 = deserialize(data);
>
> assert(b2.toString() == "derived");
> ------------------
>
> The data stream should contain enough info about the instance to
> reconstruct the exact derived type.
>
> --bb

Yes, I understood and showed yet another feature which is quite hard to implement.