
4 Jun
2021
4 Jun
'21
5:48 p.m.
I go to a directory. I run stack install Safe I start up ghci and get the Prelude prompt. I run import Safe and I get import Safe | ^^^^^^^^^^^ Failed, no modules loaded. I'm once again frustrated. I try to load this hs file {-# LANGUAGE ViewPatterns #-} {-# LANGUAGE NoMonomorphismRestriction #-} import Safe lookupDefault :: Eq a => a -> b -> [(a,b)] -> b lookupDefault k _ (lookup k -> Just s) = s lookupDefault _ d _ = d headTup :: (a, [t]) -> [t] headTup (headMay . snd -> Just n) = [n] headTup _ = [] headNil :: [a] -> [a] headNil (headMay -> Just x) = [x] headNil _ = [] with the same result. What do I need to do? -- ⨽ Lawrence Bottorff Grand Marais, MN, USA borgauf@gmail.com