How do I make a @FetchAll-like auto-updating property that depends on an input value?

[tikitu]

This feels like a very naive question, but I can't see what the equivalent of @FetchAll would be when I want it to depend on some input parameter, even a let property.

public struct TaxonView: View {
    let focused: [Taxon.ID]
    @FetchAll(Taxon.all.where { focused.contains($0) }) var taxa // Cannot use instance member 'focused' within property initializer; property initializers run before 'self' is available
    var body: some View { Text("todo") }
}

I understand the error, but I don't understand what I should do to get the equivalent effect (in particular, that taxa would post updates if the database rows changed).

[stephencelis]

You can do so in a custom initializer. Here's an example from the Reminders demo:

https://github.com/pointfreeco/sharing-grdb/blob/27aa92082156aaaecd002620ff200723eaf3f239/Examples/Reminders/RemindersDetail.swift#L24

This is similar to how Apple constructs dynamic queries for SwiftData.