network.cgi - incomplete translation of code to javascript - Haskell-Cafe

5 Aug 2010


      i try to use the Network.CGI package from darcs. my testing uses the
        example code from the webpage 'practical web programming in
        haskell' 
        
        http://www.haskell.org/haskellwiki/Practical_web_programming_in_Haskell#Gett...
        
        specifically the example with code:
        
        import Network.CGI
        import Text.XHtml
         
        inputForm = form << [paragraph << ("My name is " +++ textfield
        "name"),
                             submit "" "Submit"]
         
        greet n = paragraph << ("Hello " ++ n ++ "!")
         
        page t b = header << thetitle << t +++ body << b
         
        cgiMain = do mn <- getInput "name"
                     let x = maybe inputForm greet mn
                     output $ renderHtml $ page "Input example" x
         
        main = runCGI $ handleErrors cgiMain
        -- Get the value of an input variable, for example from a form. 
        -- If the variable has multiple values, the first one is
        returned.
        -- getInput :: String -> CGI (Maybe String)
        
        this runs (runghc) and produces the output:
        
        <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
        "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
        <html xmlns="http://www.w3.org/1999/xhtml"
        ><head
          ><title
            >Input example</title
            ></head
          ><body
          ><form
            ><p
              >My name is <input type="text" name="name" id="name"
                 /></p
              ><input type="submit" value="Submit"
               /></form
            ></body
          ></html
        >
        
        which is clearly not producing the second part of the code,
        namely output a greeting.
        the same happens with the next example, using cookies, where
        from two options for pattern matching only the first is include
        in the javascript.
        
        i assume that i do something wrong - but what?
        
        any help is appreciated!
        andrew

network.cgi - incomplete translation of code to javascript

Andrew U. Frank

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