------------------------------------------------------------------------------
-- Example for CGI programming in Curry:
-- a form with a text input field and two event handlers
------------------------------------------------------------------------------

import HTML.Base

main :: IO HtmlForm
main = return $ form "Question"
           [htxt "Enter a string: ", textfield tref "",
            hrule,
            button "Reverse string"   revhandler,
            button "Duplicate string" duphandler]

 where
  tref free

  revhandler env = return $ form "Answer"
          [h1 [htxt $ "Reversed input: " ++ reverse (env tref)]]

  duphandler env = return $ form "Answer"
          [h1 [htxt $ "Duplicated input: " ++ env tref ++ env tref]]

-- Compile and install the CGI program by:
-- 1. Install html package:
--    > cypm add -d html && cypm install
-- 2. Install executable `curry-makecgi`:
--    > cypm install html
-- 3. Install executable `html-cgi`:
--    > cypm install html-cgi
-- 4. Install executable `curry-cpnsd` (Curry Port Name Server)...
--    > cypm install cpns
--    ...and start it:
--    > curry-cpnsd start
-- 
-- Now you can compile the web script:
--    > curry-makecgi -o ~/public_html/revdup.cgi RevDup
-- If the web server is configured to execute CGI script,
-- one can execute the web page.