[zozbot234]

How? The slide deck calls it a "lenient" evaluation order, and doesn't really say how to make an explicit choice of what cases should be tried first. So it seems to have all the same problems as naïve Prolog.

[disconcision]

exact semantics are given here: https://simon.peytonjones.org/assets/pdfs/verse-conf.pdf. runtime efficiency isn't specifically addressed afaict