Unlang policy to remove duplicate attributes from reply?

[tach yon]

Hello,

I've spent many hours searching the docs, examples, list posts, etc, plus AI generators - testing as many permutations I can think of - trying to find the correct syntax and method to do this with Unlang, but nothing seems to work 🙁


I'll try to explain in sudo-code what I mean:

if (number of Framed-IP-Address attributes > 1) {
    update control {
        # Save the first Framed-IP-Address to a temporary String (because I read ipaddr type isn't available).
        &Tmp-String-0 := &reply:Framed-IP-Address[0]
    }
    update reply {
        # Remove all Framed-IP-Address entries currently in the reply.
        &Framed-IP-Address !* ANY
        # Re-create Framed-IP-Address with the first value we saved temporarily.
        # Cast as ipaddr because Framed-IP-Address needs that data type.
        &Framed-IP-Address := (ipaddr) &control:Tmp-String-0
    }
}


Everything I've tried is either invalid syntax, or a comma is expected after the cast statement, or freeradius cannot resolve to IP address, or it just doesn't work. It's starting to drive me crazy 🙁

If anyone could please help me understand what I'm doing wrong, it would be very much appreciated. Thank you in advance for your time and consideration!