Re: Implementation of "until"

Replacing an infinite loop with an exception sounds like a benefit to me. While until is technically as strict as the predicate, if the predicate doesn't evaluate at least to WHNF it's "const True|False", so I think David's analysis is correct. WRT strictness analysis, I think the modified annotation means that the final argument will be evaluated at most once. I know that further analysis can benefit from knowledge of one-shot semantics, but without an actual example it's hard for me to say how important that is in this case. John L.