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    <div class="moz-cite-prefix">I tried it another way more like
      explained on this page : 
      <a class="moz-txt-link-freetext" href="http://www.seas.upenn.edu/~cis194/spring13/lectures/02-ADTs.html">http://www.seas.upenn.edu/~cis194/spring13/lectures/02-ADTs.html</a><br>
      <br>
      so I tried this : <br>
      <br>
      parseMessage :: [Char] -> [Char]<br>
      parseMessage s<br>
      case Errornumber of <br>
          IsDigit Errornumber  -> "Geldige string"<br>
          otherwise            -> "Ongeldige string"<br>
        where<br>
            Error = s words<br>
            Errornumber = Error(ErrorNumber _ _ )<br>
            Errorcode = Error(_ Errorcode _ )<br>
      <br>
      but now I cannot use where :( <br>
      <br>
      Roelof<br>
      <br>
      <br>
      <br>
      <br>
      Roelof Wobben schreef op 23-2-2015 om 16:10:<br>
    </div>
    <blockquote cite="mid:54EB42DB.6020509@home.nl" type="cite">
      <meta content="text/html; charset=utf-8" http-equiv="Content-Type">
      <div class="moz-cite-prefix">Oke, <br>
        <br>
        Then I make there a mistake,<br>
        <br>
        What I try to do is to send the file to parseMessage and let
        IsValid check if it´s have the right format. <br>
        <br>
        Then after the where I try to check if the function isValid
        returns true or false. <br>
        <br>
        Roelof<br>
        <br>
        <br>
        Konstantine Rybnikov schreef op 23-2-2015 om 16:03:<br>
      </div>
      <blockquote
cite="mid:CAAbahfS0Sq0hGJuis5hzLj5ZTzQALdZrAEq6AevjMUDSsnaa5g@mail.gmail.com"
        type="cite">
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          <div>
            <div>
              <div>Roelof,<br>
                <br>
              </div>
              You defined isValid function in the upper-scope first, and
              then you defined a symbol (variable) that re-wrote that
              name to something different (string "Geldige string").
              That's why you get an error saying it doesn't expect
              arguments.<br>
              <br>
            </div>
            My suggestion is to rename second isValid.<br>
            <br>
          </div>
          Good luck.<br>
        </div>
        <div class="gmail_extra"><br>
          <div class="gmail_quote">On Mon, Feb 23, 2015 at 4:50 PM,
            Roelof Wobben <span dir="ltr"><<a moz-do-not-send="true"
                href="mailto:r.wobben@home.nl" target="_blank">r.wobben@home.nl</a>></span>
            wrote:<br>
            <blockquote class="gmail_quote" style="margin:0 0 0
              .8ex;border-left:1px #ccc solid;padding-left:1ex">
              <div bgcolor="#FFFFFF" text="#000000">
                <div>Chaddaï Fouché schreef op 23-2-2015 om 13:20:<br>
                </div>
                <span class="">
                  <blockquote type="cite">
                    <div dir="ltr">
                      <div>Note that Roelof is doing the CIS 194
                        Homework <a moz-do-not-send="true"
                          href="http://www.seas.upenn.edu/%7Ecis194/fall14/hw/03-ADTs.pdf"
                          target="_blank">http://www.seas.upenn.edu/~cis194/fall14/hw/03-ADTs.pdf</a>
                        (the older version of fall2014, not the one
                        currently running). This is much clearer than
                        Roelof's description, and gives among other
                        information an algebraic datatype to represent
                        log messages.<br>
                        <br>
                        <br>
                        -- <br>
                      </div>
                      Jedaï<br>
                    </div>
                  </blockquote>
                  <br>
                </span> Correct and Im trying to do exercise 1 of Week
                2,<br>
                <br>
                I have tried this solution : <br>
                <br>
                -- | Main entry point to the application.<br>
                {-# OPTIONS_GHC -Wall #-}<br>
                <br>
                module LogAnalysis where<br>
                <br>
                import Log;<br>
                import Data.Char (isLetter, isDigit) <br>
                <br>
                isValid :: [Char] -> Bool <br>
                isValid s = go (words s)<br>
                    where<br>
                      go ([a]:b:_) = isLetter a && all isDigit b<br>
                      go _         = False <br>
                <br>
                parseMessage :: [Char] -> [Char]<br>
                parseMessage s = isValid s <br>
                    where <br>
                        isValid = "Geldige string"<br>
                        _       = "Ongeldige string"<br>
                <br>
                -- | The main entry point.<br>
                main :: IO ()<br>
                main = do<br>
                    putStrLn $ parseMessage "I 4764 He trusts to you to
                set them free," <br>
                <br>
                <br>
                but I see this error message : <br>
                <br>
                <div>src/LogAnalysis.hs@16:18-16:27 </div>
                <div><span>Couldn't match expected type ‘[Char] ->
                    [Char]’ with actual type </span>
                  <div style="font-size:14px">[<span>Char</span>]</div>
                  <span> The function </span>
                  <div style="font-size:14px"><span>isValid</span></div>
                  <span> is applied to one argument, but its type </span>
                  <div style="font-size:14px">[<span>Char</span>]</div>
                  <span> has none</span><span title="Click to show/hide
                    extra information"> …</span><span
                    style="display:inline"> In the expression: isValid s
                    In an equation for ‘parseMessage’: parseMessage s =
                    isValid s where isValid = "Geldige string" _ =
                    "Ongeldige string"<br>
                    <br>
                    <br>
                  </span></div>
                <br>
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              <br>
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