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You can reach the person managing the list at beginners-ow...@haskell.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Beginners digest..." 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 <markus.l...@gmail.com> Subject: Re: [Haskell-beginners] how to feel free of the Implementation of Data structure To: beginners@haskell.org Message-ID: <aanlktinuvs6i2yls-x3qx2ew5x-cwedrzyhrc+17o...@mail.gmail.com> 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, ??? <wux...@gmail.com> wrote: > :) Thanks. > > 2011/3/24 Brent Yorgey <byor...@seas.upenn.edu>: > > 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 > > Beginners@haskell.org > > http://www.haskell.org/mailman/listinfo/beginners > > > > > > -- > ---------------- > ??? > > _______________________________________________ > Beginners mailing list > Beginners@haskell.org > http://www.haskell.org/mailman/listinfo/beginners > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://www.haskell.org/pipermail/beginners/attachments/20110325/984c97fd/attachment-0001.htm> ------------------------------ _______________________________________________ Beginners mailing list Beginners@haskell.org http://www.haskell.org/mailman/listinfo/beginners End of Beginners Digest, Vol 33, Issue 35 *****************************************