__traits and determining all overridable functions

[Steven Schveighoffer]

Hi,

I was thinking of making a template that derives from an object, but 
intercepts all calls to virtual functions automatically.  This could be used 
for something like RMI or .net Remoting to allow a call to either execute a 
method locally or in an object on a server if connected.

I thought maybe I could use __traits to determine all virtual functions, 
then override them using a mixin.  I thought __traits was a compile-time 
function, and so I thought I could create a compile-time-function that 
returns a string defining all virtual functions.

However, in doing so I find that the function does not work correctly, and 
in addition, the argument to __traits for isVirtualFunction does not take a 
string, but the result of __traits allMembers is an array of strings.  I 
think it would be more useful if isVirtualFunction and the other isXX would 
take either a string or the direct statement.  For example:

__traits(isVirtualFunction, "A.foo")
would be the same as:
__traits(isVirtualFunction, A.foo)

Then I could do:

foreach(x; __traits(allMembers, A))
    if(__traits(isVirtualfunction, "A." ~ x))
        // append to string that redefines virtual function.

Second, the mixin doesn't work.  I hard-coded the function to output the 
string I was trying to build.  Therefore, the compiler should be able to 
execute the method in compile time, and pre-determine the string to return. 
But the mixin just defines the function name that I am calling as a member. 
i.e., I define my function above as:

string redefFunctions(T)();

and my mixin in the class is:

mixin(redefFunctions!(A)());

But when I build my class, there is a member redefFunctions!(A) instead of 
the list of virtual functions I expected to override.

Any ideas?  Is there another way this will work?  If not, is it possible to 
make it so it would work :) ?

-Steve