Serialization + semantics of toString

[Jacob Carlborg]

On 11/13/09 00:13, aarti_pl wrote:
> Andrei Alexandrescu pisze:
>  > But that being said, I'd so much want to start thinking of an actual
>  > text serialization infrastructure. Why develop one later with the
>  > mention "well use that stuff for debugging only, this is the real
> stuff."
>  >
>  > Andrei
>
> You might want to see my serialization library for D.
>
> I think that it is worth noting as it manages to achieve the goal:
> same data - completely different output. Because this output might be
> defined by user in the way she wants, it seems that this can work
> exactly the way toString should work.
>
> It is achieved by using Archive classes which makes proper formatting,
> and which are completely independent from data being printed. Initial
> design is based on C++ Boost. I just extended concept a bit and adopted
> it to D.
>
> Basic interface for serialization is like this:
>
> auto serializer = Serializer!(TextArchive);
> //It might be also e.g.:
> //auto serializer = Serializer!(JsonArchive);
> auto input = new TransparentClass(-21, 2.11, "text1", 128, -127);
> auto output = serializer.dump(input);
> assert(serializer.load!(TransparentClass)(output) == input);
>
> In case of transparent classes (every field is public) you don't need
> any method inside of serialized class/struct.
>
> In case of opaque classes there is enough to:
> 1. add mixin inside:
> mixin Serializable;
> or
> 2. add template method:
> void describeUdt(T)(T arch) {
> arch.describeStaticArray(array, array.stringof);
> }

Or you could use arhc.typeof[i] to access/set the values (even private) 
of a struct/class.

> This is all what is necessary to print every possible class/struct in
> whatever format you want.
>
> Because of limitations of D I couldn't achieve serialization of classes
> from base pointer. It was because of fact that template methods are not
> virtual.
>
> Recently I didn't have time to work on it, but if you think it's worthy
> and eventually might be included in Phobos, I would be interested to
> work on it further. But I would definitely need some code/concepts review.
>
> Unfortunately there is rather poor documentation. But you can find a lot
> of unit tests in examples directory.
>
> It's Boost licensed so no worries :-)
>
> BR
> Marcin Kuszczak
> (aarti_pl)