loop through specific class members

[Sergey Gromov]

Wed, 21 Jan 2009 12:48:07 +0100, Trass3r wrote:

> Christopher Wright schrieb:
>> On the other hand, you can get the non-final, non-private methods of a 
>> class with something like:
>> foreach (member; __traits (allMembers, Class))
>> {
>>     foreach (overload; __traits (getVirtualFunctions, Class, member))
>>     {
>>         // do stuff
>>     }
>> }
>> 
>> Naturally, __traits and foreach don't mix, so you'll have to use 
>> template recursion. This is pretty damn ugly.
>> 
> 
> But why doesn't that work? It doesn't even work when forced to run at 
> compile time by CTFE.
> Had a look at the compiler code, it uses the same mechanism as 
> pragma(msg, for example, so shouldn't something like the above 
> theoretically be possible?

foreach() is a runtime construct.  It may be *interpreted* at
compile-time, but it's interpreted as if it were run time nevertheless.
It dynamically changes the value of 'member' variable.

pragma() and __traits() are compile-time constructs.  They are fully and
statically expanded before anything is being interpreted and cannot
handle dynamically changing variables.