Reflection: potential possibilities

[gareis]

Daniel Keep wrote:
> 
> Thomas Kuehne wrote:
>> gareis schrieb am 2007-06-08:
>>> Using TypeInfo, ClassInfo, and such, you can gain a fair bit of 
>>> knowledge about a class at runtime.
>>> You could also modify TypeInfo and ClassInfo. Flectioned does this in 
>>> allowing you to redirect functions.
>>> You should then be able to create a class at runtime and instantiate it.
>>> The problem, of course, is connecting compile-time code to run-time 
>>> classes. This gives two options:
>>> 1. Use CTFE to create classes based on other classes, or just use mixins 
>>> and avoid the creation issue entirely.
>>> 2. Use a parent class. Virtual means it just works. (Hopefully.)
>>> I haven't tried these, but it sounds like, if this works, and combined 
>>> with function arrays, it should be possible to come up with a program 
>>> that writes and then runs itself at runtime. (You need function arrays 
>>> to support arbitrary numbers of methods per class.)
>>> The main issues are:
>>>   - Does this work at all? Can I create a ClassInfo / TypeInfo object 
>>> and then instantiate from it, or do I always need to go from a 
>>> preexisting class? Can I actually modify a ClassInfo object and have the 
>>> changes reflected in the program? Flectioned seems to indicate so, since 
>>> you can redirect functions.
>>>   - If it works, how can I link compile-time code to run-time classes?
>>> Any thoughts?
>>> Worst case, for my project, I'll have to use CTFE to parse ClassInfo and 
>>> then use mixins to create the classes.
>> If all your class member functions are functions have the signature
>> 	T functionName(TypeInfo[], void*)
>> and the dynamic classes use a common base class like:
>>
>> # class DynObject : Object{
>> # 	T call(char[] name, TypeInfo[], void*);
>> # }
>>
>> This can be implemented via Flectioned. The problem is how variadic
>> functions are implemented in D - especially GDC on 64bit systems.
>>
>> Thomas
> 
> An alternative might be to use variant arguments; either std.boxer, or
> <plug
> class="shameless">http://www.prowiki.org/wiki4d/wiki.cgi?DanielKeep/Variant</plug>.
> 
> I'd say more, but I'm not entirely sure what you're trying to do...
> 
> 	-- Daniel

Basically a version of this: http://www.ayende.com/projects/rhino-mocks.aspx

It'll be mainly for my own code, which doesn't use varargs, but if I do 
anything useful with it, I'll release it.

It sounds like it'll take maybe a week to set up the core of it. D is 
fast :) As well as Thomas Kuehne doing all the work before I got here. 
Thank you for that.