[Haskell-cafe] hugs type inference
ross at soi.city.ac.uk
Thu Oct 27 19:14:56 EDT 2005
On Thu, Oct 27, 2005 at 11:02:48PM +0200, Christian Maeder wrote:
> Hugs.Base> :t toRational 1 / 2
> toRational 1 / 2 :: Real a => Ratio Integer
> ghci yields:
> Prelude> :t toRational 1 / 2
> Warning: Defaulting the following constraint(s) to type `Integer'
> `Real a' arising from use of `toRational' at
> In the first argument of `(/)', namely `toRational 1'
> toRational 1 / 2 :: Rational
They're both telling you the same thing:
1 :: Num a => a
toRational 1 :: Real a => Rational
toRational 1 / 2 :: Real a => Rational
GHCi shows the type after defaulting; Hugs shows the type before, but
this can be changed with the +T option.
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