On 2018-06-06 15:28, Arafel wrote:
Hi,
What is the state of runtime introspection in D, specifically for
classes? Is there any way to get *at runtime* the (public or otherwise
accessible) members of a class?
I have had a look as TypeInfo_Class [1], but apparently I can only get a
list of types and offsets... which would be almost good enough, if not
because the names of the members are missing, or at least I haven't been
able to find them.
In this case, what I'm trying to do is to serialize / dump / print the
contents of an object (class instance) without knowing its actual
runtime type.
Before somebody suggests compile time introspection, the "main" code
where this routine lives only provides a base class, and it's up to
dlopen'ed plugins to provide the actual implementation... so I'm sorry
but no compile-time solution can possibly work.
Also, having each derivative class provide their own dumping information
is not practical, I'd rather have it automated.
I know it might not be the most idiomatic D, but as somebody with mostly
a Java background (with some C and just a bit of C++) it seems something
really straightforward to me: myObject.getClass().getFields() [2].
Also, I know I could add some UDA or even crawl the modules and have
this information generated automatically at compilation time and added
to the type itself in a member, and I might even end up doing it, but
honestly, I think it's something that the language should provide in a
kind of easy / accessible way.
Powerful as compile-time introspection is, I think runtime shouldn't be
forgotten either :-)
The simplest, in my opinion would be to for the subclasses to register
themselves with the serializer. This is how Orange works to allow
serializing through base class references [1]. The use compile time
introspection on the subclass and serialize that as usual.
[1]
https://github.com/jacob-carlborg/orange/blob/master/tests/BaseClass.d#L73
--
/Jacob Carlborg
