Parse Error on Input '<-' : Haskell

Question

I am taking input from the user and the code is as follows:

putStrLn $ "Enter number"
num <- getLine
main = print $ num

When I run this code, the compiler gives following error:

ra.hs:10:5: parse error on input `<-'

How can I remove this error? I have tried to use spaces, as well as tab characters, but the error persists. Please help.

Perhaps you should paste your entire code and try to format it properly: stackoverflow.com/help/formatting — Mokosha
– Mokosha, Commented Nov 26, 2014 at 0:49

jamshidh · Accepted Answer · 2014-11-26 00:51:50Z

5

You have to move all of your code into main

main = do
    putStrLn "Enter number"
    num <- getLine
    print num

The area outside of main is for declarations, etc. You use <- inside of a do.

Also, you don't need the extra $'s when there is a single parameter.

answered Nov 26, 2014 at 0:51

jamshidh

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Comments

Tsuneo Yoshioka · Accepted Answer · 2014-11-26 02:25:22Z

0

It just works for me, if I put lines to inside main.

main:: IO ()
main = do
    putStrLn $ "Enter number"
    num <- getLine
    print $ num

answered Nov 26, 2014 at 0:54

Tsuneo Yoshioka

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