I can use `std.traits.getSymbolsByUDA` to get all the members of a class that have a particular UDA `getSymbolsByUDA(ValueType, UDA)`.

But how do I get the values with it?

Is there a more convenient way than `__traits(getMember, value, getSymbolsByUDA(ValueType, UDA)[0].stringof)`?

On Tuesday, 2 October 2018 at 03:30:50 UTC, Jonathan wrote:
> I can use `std.traits.getSymbolsByUDA` to get all the members of a class that have a particular UDA `getSymbolsByUDA(ValueType, UDA)`.
>
> But how do I get the values with it?
>
> Is there a more convenient way than `__traits(getMember, value, getSymbolsByUDA(ValueType, UDA)[0].stringof)`?

You can use .tupleof and hasUDA instead:

import std.traits;
import std.stdio;

enum uda1;
enum uda2;

class S {
    @uda1 int a = 1;
    @uda2 int b = 2;
    @uda1 int c = 3;
    @uda2 int d = 4;
}

void main() {
    auto s = new S;

    static foreach (i, _; S.tupleof) {
        static if (hasUDA!(_, uda1))
            writefln("uda1 (%s): %s", __traits(identifier, _), s.tupleof[i]);
    }

    static foreach (i, _; S.tupleof) {
        static if (hasUDA!(_, uda2))
            writefln("uda2 (%s): %s", __traits(identifier, _), s.tupleof[i]);
    }
}