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Description
Using Data.JSString.pack gives incorrect results. For example:
import Data.JSString (pack)
main :: IO ()
main = print $ pack $ fst $ foldr (select (== 'a')) ([], []) "ababababa" -- "a"
where
-- taken from Data.OldList
select p x ~(ts, fs) | p x = (x:ts, fs )
| otherwise = (ts , x:fs)Outputs "a", and it should output "aaaaa". But if we remove the ~ for irrefutable patterns, we get correct results:
import Data.JSString (pack)
main :: IO ()
main = print $ pack $ fst $ foldr (select (== 'a')) ([], []) "ababababa" -- "aaaaa"
where
-- taken from Data.OldList
select p x (ts, fs) | p x = (x:ts, fs )
| otherwise = (ts , x:fs)I believe this issue has something to do with GHCJS packing the lazy String too early, before the fold is complete.
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luite commentedon Mar 25, 2020
I think this may be a bug related to the handling of selector thunks. It looks like they're not always correctly updated