Koos Zevenhoven writes:
As a random example, (root @ mean @ square)(x) would produce the right order for rms when using .
Hardly interesting. :-) The result is an exception, as root and square are conceptually scalar-to-scalar, while mean is sequence-to-scalar.
I suppose you could write (root @ mean @ (map square)) (xs), which seems to support your argument. But will all such issues and solutions give the same support? This kind of thing is a conceptual problem that has to be discussed pretty thoroughly (presumably based on experience with implementations) before discussion of order can be conclusive.