When I got home from work, Corion's reply was the only response at that time.
I followed the link he'd provided, followed some more links from that, then hit "reply".
As I was composing, I noticed I now had a reply from you and thought: "Oh good, more information, I'll look at that in a minute."
— and when I did, I then thought: "Hmmm, that looks familiar."
Anyway, I've only just found it, perhaps you've used it.
I noticed there's an additional argument:
Is %params as straightforward as it seems?
I'm thinking maybe issues with values that are references to data structures,
as opposed to simpler (Str, Int, etc.) values.