[Haskell-cafe] GHC TV station?

[Sylvain Henry]

Some ways to fix the given code:

strlen :: IO ()
strlen = do  putStr "Enter a string: " >> do
                   xs <-  getLine
                   putStr "The string has "
                   putStr (show (length xs))
                   putStr " characters"

strlen :: IO ()
strlen = do  putStr "Enter a string: "
              do
                   xs <-  getLine
                   putStr "The string has "
                   putStr (show (length xs))
                   putStr " characters"

strlen :: IO ()
strlen = do  putStr "Enter a string: "
              xs <-  getLine
              putStr "The string has "
              putStr (show (length xs))
              putStr " characters"


On 15/05/2018 18:13, Sylvester via Haskell-Cafe wrote:
> strlen in Hutton 2ed 10.5 Derived primitives => run on Windows 7 Haskell
> Platform 8.2.2
> strlen :: IO ()
> strlen = do  putStr "Enter a string: "
>                     xs <-  getLine
>                     putStr "The string has "
>                     putStr (show (length xs))
>                     putStr " characters"
> ===================================================
> GHCi, version 8.2.2: http://www.haskell.org/ghc/  :? for help
> [1 of 1] Compiling Main             ( C:\strlen.WhiteSpaced.hs, interpreted
> )
>
> C:\strlen.WhiteSpaced.hs:2:14: error:
>      Parse error in pattern: putStr
>      Possibly caused by a missing 'do'?
>    |
> 2 | strlen = do  putStr "Enter a string: "
>    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^...
> Failed, no modules loaded.
> Prelude>
> ==================================================
> strlen :: IO ()
> strlen = do {putStr "Enter a string: ";
>                     xs <-  getLine;
>                     putStr "The string has ";
>                     putStr (show (length xs));
>                     putStr " characters"}
> =================================================
> GHCi, version 8.2.2: http://www.haskell.org/ghc/  :? for help
> [1 of 1] Compiling Main             ( C:\strlen.Bracesed.hs, interpreted )
> Ok, one module loaded.
> *Main>
>
>
>
> --
> Sent from: http://haskell.1045720.n5.nabble.com/Haskell-Haskell-Cafe-f3074699.html
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