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Today's Topics:
1. Re: how to feel free of the Implementation of Data structure
(Markus L?ll)
----------------------------------------------------------------------
Message: 1
Date: Fri, 25 Mar 2011 12:17:15 +0200
From: Markus L?ll <[email protected]>
Subject: Re: [Haskell-beginners] how to feel free of the
Implementation of Data structure
To: [email protected]
Message-ID:
<[email protected]>
Content-Type: text/plain; charset="utf-8"
There's also ListLike: http://hackage.haskell.org/package/ListLike
--
Markus L?ll
On Fri, Mar 25, 2011 at 6:32 AM, ??? <[email protected]> wrote:
> :) Thanks.
>
> 2011/3/24 Brent Yorgey <[email protected]>:
> > On Thu, Mar 24, 2011 at 06:34:57PM +0800, ??? wrote:
> >>
> >> 2.
> >> f1 :: (Integral a) => a -> String
> >> f2 :: (Integral a) => String -> a
> >>
> >> pipe = f1 . f2
> >> It is clear that pipe is String -> String,
> >
> > Actually, this code will give an "ambiguous type" error, since the
> > compiler cannot figure out what type 'a' should be. And the type that
> > is chosen may make a difference for the behavior.
> >
> >> but.(1)How can I know what instance that 'a' is.
> >> (2)How can I determine what instance of 'a' is.
> >
> > If you know what type you want to use for 'a' you can specify it with
> > a type annotation, like this:
> >
> > pipe = f1 . (f2 :: String -> Int)
> >
> > -Brent
> >
> > _______________________________________________
> > Beginners mailing list
> > [email protected]
> > http://www.haskell.org/mailman/listinfo/beginners
> >
>
>
>
> --
> ----------------
> ???
>
> _______________________________________________
> Beginners mailing list
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>
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