10 Apr
2019
10 Apr
'19
3:40 p.m.
My apologies, I've found a better way to express it and am retracting this proposal: mwhen cond a = fold [a | cond] a <> mwhen p b <> c <> mwhen q d = (fold.fold) [[a],[b|p],[c],[d|q]] This also works with other folds without touching monoid newtype wrappers. I had hang-ups about bool as I don't feel like you can 'read off' the ordering, and thought mempty might be a common argument , but neither of those apply here. Thank you for your replies.