Say I have code like below. If I comment the leftover in main, I got (Just
"L1\n", Just "L2\n", Just "L3\n", Just "L4\n"). But if I did not comment
the leftover, then I got (Just "L1\n", Just "L1\n", Just "", Just "L2\n").
Why is not it (Just "L1\n", Just "L1\n", Just "L2\n", Just "L3\n")?
takeLine :: (Monad m) => Consumer ByteString m (Maybe ByteString)
takeLine = do
mBS <- await
case mBS of
Nothing -> return Nothing
Just bs ->
case DBS.elemIndex _lf bs of
Nothing -> return $ Just bs
Just i -> do
let (l, ls) = DBS.splitAt (i + 1) bs
leftover ls
return $ Just l
main = do
m <- runResourceT $ sourceFile "test.simple" $$ (do
a <- takeLine
leftover $ fromJust a
b <- takeLine
c <- takeLine
d <- takeLine
return (a, b, c, d))
print m
--
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