Can "isTemplate" return true for a non-function class member in D?

Question

I've got a list of class members: __traits(allMembers, SomeType). And I use a trait __traits(isTemplate, member) for some element member from the list. Consider the result of the trait is true. Does this mean that the member is a function? Or can something else be template in the list from allMembers?

Answer 1

It doesn't mean it's a function, it means it's a template. That template could either be a templated function, or indeed a template itself.

An example:

import std.stdio;
struct Test{
    void fee(T)(){}
    template fi(T){
        void fo(){} // wont get tested...
    }
    void fum(){}
} 

void main(){
    foreach(member; __traits(allMembers, Test)){
        writefln("%s isTemplate: %s", member, __traits(isTemplate, mixin("Test."~member)));
    }
}

Output:

fee isTemplate: true
fi isTemplate: true
fum isTemplate: false

The thing that is probably tripping you up is you lacking the mixin. If mixin("Test."~member) wasn't there, then isTemplate would be testing if fi is a template, or fo or fum, and they're not templates as they dont exist in that namespace.

They only exist in the Test structs namespace.