29 May
2009
29 May
'09
8:04 p.m.
On Friday 29 May 2009 22:10:51 Bryan O'Sullivan wrote:
myFloat = try (symbol "-" >> float >>= return . negate) <|> try float <|> (integer >>= return . fromIntegral)
Any time you see ">>= return .", something is being missed. Use liftM or <$> instead, i.e. "fromIntegral <$> integer" instead of "integer >>= return . fromIntegral".
I don't undersdand what is being missed. liftM f m1 = do { x1 <- m1; return (f x1) } so liftM fromIntegral integer will result the same. Is it then not just a convenience? Bartek