Runtime introspection, or how to get class members at runtime Fin D

[evilrat]

On Friday, 8 June 2018 at 08:06:27 UTC, Arafel wrote:
> On Thursday, 7 June 2018 at 13:07:21 UTC, evilrat wrote:
>>
>> I don't think so. It clearly states that children must mixin 
>> too, which can mean it just grabs symbols in scope only, and 
>> base class has no way of knowing about its subclasses. It also 
>> has "agressive mode" that will make metadata for all public 
>> symbols(?) it can walk, this may or may not be helpful 
>> depending on your requirements.
>>
>
> Yes, that's what I understood from looking at it, but perhaps I 
> was just missing something. I wonder though how the "agressive 
> mode" would work with separate compilation / dlopen'ed 
> libraries. Perhaps I should give it a try and see what happens.
>
>> Besides there is no way(not that I am aware of) to make self 
>> registering stuff happen, you still need to call it somewhere. 
>> The most transparent option is probably just doing a mixin in 
>> each module that performs registration of all module symbols 
>> in module ctor.
>> The point is that there is absolute requirement to make 
>> explicit call for that, be it a module ctor mixin, class mixin 
>> or even user provided registration both at compile time or run 
>> time.
>> But since it is MIT licensed you can probably use the code as 
>> the starting point and adjust to your own needs.
>>
>>
>>
>> BTW plug-ins is something that is right now possible on 
>> Linux(not sure about support on other *NIX systems), but in a 
>> very primitive form on Windows.
>> This is related to DLL support issues(such as type information 
>> not being passed across process/DLL boundaries), these issues 
>> also may include runtime issues as well such as inability to 
>> delegate the GC, which will mean there will be 2(or more) 
>> concurrent running GC's. But again I am not aware of the 
>> current situation.
>
> Well, I'm already tightly coupled to linux, so this is not a 
> big concern for me :-)
>
> I'll keep trying, as I said, my intention was to let plugin 
> writers do it as easily as possible, but well, adding some kind 
> of "register" function might be necessary in the end...
>
> A.

Yep. Like I said probably the easiest to use way is to place 
single call in each module. And there probably no other solution, 
because modules creates sort of isolated graph via imports. And I 
am not aware of any way to get list of modules passed in with 
compiler invocation to perform some sort of centralized one-liner 
registration.

But anyway look at this, might give some tips on how it can be 
done

mixin
https://github.com/Circular-Studios/Dash/blob/b7d589ad4ca8993445c136b6a4ae170932bb7962/source/dash/components/component.d#L208

(note that it uses static this() - module constructor. I think 
this behavior was changed around 2015-2016 and now it will cause 
cyclic dependency errors when modules with ctors import each 
other)

usage
https://github.com/Circular-Studios/Dash/blob/b7d589ad4ca8993445c136b6a4ae170932bb7962/source/dash/components/lights.d#L12