[Haskell-cafe] Reading showables
newhoggy at gmail.com
Sun Dec 7 19:16:10 EST 2008
So "show . read" and "\x -> show (read x)" are actually mean different
Also, I never suspected that something like this should succeed:
putStrLn $ (read . show) $ "!@#%$^DFD"
On Mon, Dec 8, 2008 at 12:38 AM, Thomas Hartman <tphyahoo at gmail.com> wrote:
> By convention, read . show is supposed to be id.
> However, in real life, this is often not the case. It all depends on
> the implementor, and this is a convention that seems to be broken
> pretty frequently.
> Often there is a show instance with no read or vice versa, and
> sometimes even when there is both read and show they are not inverses.
> main = show . read
> Am 7. Dezember 2008 14:11 schrieb John Ky <newhoggy at gmail.com>:
> > Hi,
> > Is there a way to read Showables?
> > main = do
> > putStrLn $ show $ read
> > Thanks
> > -John
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