[Haskell-beginners] Please, help me for myFirstCode

[David McBride]

2) No.

1) That is your syntax error.  You should have "ranNoInt = <something>".
The =<< operator is meant for the definition of the function.

Try this:

import System
import System.Random

main = readFile "C:\\Documents and Settings\\myHeader.txt" >>=
myExtractSentence >>= putStrLn

myExtractSentence file = do
  ranNoInt <- ranNo
  return $ ary !! ranNoInt
  where
         ranNo = randomRIO (0, n-1)
         n = length ary
         ary = lines file


On Tue, Oct 26, 2010 at 2:36 AM, Sok H. Chang <shaegis at gmail.com> wrote:

> Hello, everyone.
>
> I need help for my first code.
> I write this code for extracting one sentence from text file.
>
> The code is
>
> -----------------------------------------------------------------------------------------------------------------------
> import System
> import System.Random
>
> main = do myHeader <- readFile "C:\\Documents and Settings\\myHeader.txt"
>  putStrLn $ myExtractSentence myHeader
> myExtractSentence file = ary !! ranNoInt
>  where
>          ranNoInt =<< ranNo                        -- *mark
>          ranNo = randomRIO (0, n-1)
>          n = length ary
>          ary = lines file
>
> ----------------------------------------------------------------------------------------------------------------------
> There are two questions.
>
> 1) I've got following error message.
> Haskell>ghc --make Test01.hs -o Test
> [1 of 1] Compiling Main             ( Test01.hs, Test01.o )
>
> Test01.hs:10:9: parse error (possibly incorrect indentation)
>
> How can fix it?
>
> 2) Is it OK at "*mark" line?
>
> Thank you.
>
> S. CHANG
>
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>
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