Re: [Haskell-cafe] Trying to write 'safeFromInteger'

On Wed, 8 Apr 2009, Neil Mitchell wrote:

That seems a really weird way to write it! Who decided all auxiliary functions should be called go? (I think I'm blaming dons) - why not:

sffi :: (Integral a,Num a) => Integer -> Maybe a sffi n | toInteger n2 == n = Just n2 | otherwise = Nothing where n2 = fromInteger n

I think it is a bug, that 'fromInteger' is defined for numbers outside the range of the target type. Why is it necessary to have, say fromInteger 1000 == (232 :: Word8) ? I would not rely on this behaviour and safeFromInteger should also work, when the fromInteger method yields undefined for some Integer input.