Help with reflection?

[bitwise via Digitalmars-d]

On Friday, 10 October 2014 at 17:43:13 UTC, Kapps wrote:
> On Friday, 10 October 2014 at 17:00:01 UTC, bitwise wrote:
>> Hey, I am trying to put together a basic reflection system, 
>> but I've run into a problem. I'm not sure if this is a bug or 
>> not.
>>
>> I am trying to store method information about a class. So 
>> basically, I am using Traits to go through all members of the 
>> class, and then trying to create delegates to each member. 
>> Then, at runtime, the function will be dynamically invoked by 
>> changing the ".ptr" property of the delegate, and calling it.
>>
>> These are the errors I am getting from these 3 lines from the 
>> code below:
>>
>> //del.ptr = null;
>> -Error: CTFE internal error: unsupported assignment del.ptr = 
>> null (TestD)
>>
>> //del.funcptr = mixin("&T." ~ member);
>> -Error: CTFE internal error: unsupported assignment 
>> del.funcptr = & someFunction (TestD)
>> -Also, why has 'T' been removed after mixin?
>>
>> //del.funcptr = mixin("&SomeClass." ~ member);
>> -Error: CTFE internal error: unsupported assignment 
>> del.funcptr = & someFunction (TestD)
>
> Without looking too much at your code, the internal error seems 
> to definitely imply a bug, I recommend reporting it on the 
> issue tracker.
>
> Also, I made a Reflection module as well, you may find some of 
> the code useful (such as getting methods at compile-time and 
> invoking at run-time): 
> https://shardsoft.com/stash/projects/SHARD/repos/shardtools/browse/source/ShardTools/Reflection.d?until=45ded3019f3f05d7b68e5746d34da1de7433ccf6#1299 
> (links to a specific commit, after that I started trying to 
> unify runtime and compile-time reflection into one API which 
> gave me some troubles). It can get a bit complicated depending 
> on what your needs are, as you would need to deal with vtables 
> and interfaces depending on what you want to support. My 
> implementation definitely isn't perfect, but works for my usage.


Thanks for the help!

   I tried a workaround, which was to store the function pointer 
and then assign it to the delegate at runtime, at which point the 
compiler told me that the function pointer was not a compile time 
constant. So that may have been the root of the problem.

   Finally, I was able to get my code working by accessing the 
vtable directly like your code.

   My code is posted here:

https://github.com/bitwise-github/D-Reflection