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Automatic Code Downloading Procedure

1. A click in a link of the query form starts the downloading of the code (alternatively using multipart/mixed mime type).
2. The broser starts a wpl_handler as the document has type application/x-prolog.
3. The wpl_handler process starts a Prolog engine (configured as an active module) if necessary.
4. Then, through a call ``loadcode(File)'' the handler asks the active module to read the code.
5. The active module reads the code and compiles it.
6. wpl_handler waits for the active module to complete the compilation and writes a ``done'' message to the browser.
7. The browser receives the ``done'' message.
8.   Now, when the ``submit'' button in the form is pressed, the browser starts a wpl_questioner as a handler of the form data.
9. The wpl_questioner process translates form data to a dictionary FormData, passing it to the active module through a call answerform(FormData,FormReply).
10. The active module processes this request, and returns in FormReply a WWW page (as a term) containing the answer.
11. The wpl_questioner process translates FormReply to raw HTML and gives it back to the browser, dying afterwards. Subsequent queries proceed at 8.