Sorry HNers and P6ers.

I feel so embarrassed. I'm usually almost pathologically careful. I have an explanation if anyone wants it but I suspect an excuse is uninteresting so will skip that for now.

Instead I'll say I am now committed to trying to implement this (it's in the spec, just not yet implemented) by updating Rakudo's sort method:

https://github.com/rakudo/rakudo/blob/874e358fa5b09f94243003...

The good news is that it's (currently) about 10 lines of code. The bad news is they look very gutsy to me. Oh well. Open mouth, take responsibility, do your best and all that.