winSSQ count noRed noBlue = do {
yesRed <- [1..33] \\ noRed;
yesBlue <- [1..16] \\ noBlue;
bracket (openFile "ssqNum.txt" WriteMode) (hClose) (\hd1 -> pickSSQ
count yesRed yesBlue hd1);
return ()
}
will report:
Couldn't match expected type `IO ()' against inferred type `[()]'
In a stmt of a 'do' expression:
bracket
(openFile "ssqNum.txt" WriteMode)
(hClose)
(\ hd1 -> pickSSQ count yesRed yesBlue hd1)
However, the following works fine:
winSSQ count noRed noBlue = do
let yesRed = [1..33] \\ noRed
let yesBlue = [1..16] \\ noBlue
bracket (openFile "ssqNum.txt" WriteMode) (hClose) (\hd1 -> pickSSQ
count yesRed yesBlue hd1)
Why ?
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