[Haskell-beginners] Overloading resolution with numbers

[damodar kulkarni]

See this:
Prelude> :t 2.3
2.3 :: Fractional a => a

Hope this helps.


On Thu, Apr 5, 2012 at 7:24 PM, <j.romildo at gmail.com> wrote:

> On Thu, Apr 05, 2012 at 01:18:39PM +0000, Amy de Buitléir wrote:
> >  <j.romildo <at> gmail.com> writes:
> > > Why does (read "2" + 1) works, but (read "2.3" + 1) fail at runtime?
> >
> > Try this:
> >
> > read "2.3" + 1 :: Float
> >
> > Or this:
> >
> > read "2.3" + 1.0
> >
> > The reason that your version didn't work is because GHCi is guessing
> that you
> > want the read operation to parse an Integer, since you're adding it to 1.
>
> This is explanation does not seem to be enough once we consider the type
> of the literal 1:
>
>   Prelude> :t 1
>   1 :: Num a => a
>
> That is, the literal 1 is overloaded to any numeric type. It is not
> necessarily an Integer.
>
> Romildo
>
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-- 
Thanks and regards,
-Damodar Kulkarni
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