meInvent bbird <jobmattcon@gmail.com> writes:

On Tuesday, August 23, 2016 at 6:00:07 PM UTC+8, Ben Bacarisse wrote:

meInvent bbird <jobmattcon@gmail.com> writes:

parse error on input `\'

import System.IO
import Control.Monad

main = do
file <- readFile "hello.txt"
forM_ [5..7] (lines file) \i ->
putStrLn i

Did you mean

forM_ (lines file) (\i -> putStrLn i)

? The syntax error is that you need ()s round the lambda expression
here, but the extra list [5..7] is puzzling me.

would like to choose specified lines to display

Then replace (lines file) with an expression that gives the lines you
want. For example (take 2 (drop 4 (lines file))) (which is neater
using $ but that's not the point).

--
Ben.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

meInvent bbird <jobmattcon@gmail.com> writes:

parse error on input `\'

import System.IO
import Control.Monad

main = do
file <- readFile "hello.txt"
forM_ [5..7] (lines file) \i ->
putStrLn i

Did you mean

forM_ (lines file) (\i -> putStrLn i)

? The syntax error is that you need ()s round the lambda expression
here, but the extra list [5..7] is puzzling me.

--
Ben.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)