[Haskell-cafe] newbie questions (read, etc., with Data.ByteString.Lazy.Char8)

Don Stewart dons at galois.com
Mon Oct 6 23:19:58 EDT 2008

> Thanks for your replies.  Hoogle is pretty cool--I didn't know about that.
> I ended up with this, which is pretty close to the original (it will
> also bomb if given non-integer input):
> import qualified Data.ByteString.Lazy.Char8 as L
> import qualified Data.Maybe as M
> main = do
>          contents <- L.getContents
>          print (sumFile contents)
>              where sumFile = sum . map (fst . M.fromJust . L.readInt) . L.words
> One further problem I've encountered: My Haskell program runs under
> 'runghc', but I get a link error when compiling it (GHC 6.8.2, latest
> Ubuntu).  Any suggestions?

Oh wow, runghc is an interpreter. It is on average about 30x slower than
compiled code.

To compile, try something like:

    ghc -O2 --make A.hs

And enjoy the native codes. :)

-- Don

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