Runtime reflection idea

[Steven Schveighoffer]

On Thu, 30 May 2013 10:59:52 -0400, Adam D. Ruppe  
<destructionator at gmail.com> wrote:

> The compiler instantiates a template called RTInfo!T for every custom  
> type T that is made available through the TypeInfo class (.classinfo,  
> typeid()).
>
> The first idea with this was to do precise GC, but it can do more than  
> just that. Currently, it is totally unused in druntime. I propose we put  
> it to use to allow some runtime reflection.

http://forum.dlang.org/post/op.wcvlmg03eav7ka@localhost.localdomain

> and ModuleInfo even has a list of all classes, and all modules in a  
> program, so we could go pretty nuts with runtime stuff here.

I also want ModuleInfo to have an equivalent RTInfo member.  Walter agreed  
at the conference that it was a good idea and should be done.  See bug  
report here:

http://d.puremagic.com/issues/show_bug.cgi?id=10023

> What do you all think? It is a pretty minor change to druntime to enable  
> this kind of thing, it wouldn't get in the way of anything else -  
> druntime can still use RTInfo for its own thing when the time comes  
> without a problem -  and it seems to me like it could be easily useful  
> and convenient for some tasks.

I would like to see the necessary framework for RTInfo to allow expansion  
WITHOUT having to modify object.d.  I think this can be done, and then it  
allows anyone to insert whatever they want for RTInfo based on their own  
needs.

This would set D apart from existing runtime information frameworks, like  
Java's and C#'s, in that it's expandable, and it's selective (enabling  
runtime information might be as simple as adding UDAs).

-Steve