[Haskell-beginners] IO vars
mihai.maruseac at gmail.com
Wed Aug 29 11:04:06 CEST 2012
On Wed, Aug 29, 2012 at 10:58 AM, Corentin Dupont
<corentin.dupont at gmail.com> wrote:
> Hi all,
> there is something very basic that it seems escaped me.
> For example with the following program f and g have type IO () and I can
> thread a value between the two using a file.
> Can I do the exact same (not changing the types of f and g) without a file?
> f,g :: IO ()
> f = withFile "toto" WriteMode (flip hPutStr "toto")
> g = withFile "toto" ReadMode hGetLine >>= putStrLn
> main = f >> g
f,g :: IO ()
f = putStr "Answer: "
g = print 42
Main> f >> g
The () is threaded by >>, not the file content
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