You could also create a wrapper function that accepts [[String]] and let it deal with the inner lists. If it is pure function, then you can say *Right r -> return (<your function> r)*. This would wrap the return value from the function in IO monad. On Mon, Jan 24, 2011 at 3:44 PM, Shakthi Kannan wrote:

Hi,

I am trying to parse a .csv file and process the individual lines. Here is some code snippet (based on RWH Chapter 16 [1]):

=== test.hs ===

import Text.ParserCombinators.Parsec import System.Environment (getArgs)

parseCSV :: String -> Either ParseError [[String]] parseCSV input = parse csvFile "(unknown)" input

main = do do c <- getContents case parse csvFile "(stdin)" c of Left e -> do putStrLn "Error parsing input:" print e Right r -> mapM_ print r

=== END ===

Given an input file foo.csv:

a,b,c d,e,f g,h,i

and running the above test.hs using:

$ runghc test.hs < foo.csv

I get the following output:

["a,b,c"] ["d,e,f"] ["g,h,i"]

Instead of using mapM_ print r, how can I obtain and pass each of the above lists (for example, ["a,b,c"]) to another function for processing?

Appreciate any inputs,

Thanks!

SK

[1] RWH. Using Parsec. http://book.realworldhaskell.org/read/using-parsec.html

-- Shakthi Kannan http://www.shakthimaan.com

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