Paul L wrote:
Pardon me to hijack this thread, but I have an idea to build a different kind of Web Framework and am not sure if somebody has already done it.
The idea is to take REST further: every HTML page you see is a program in its running state (as a continuation monad). Each click on its link or form submission is seen as feeding data to resume its continuation.
So instead of writing a server-side program that responds to many CGI calls, you write a single ordinary program that describe the application logic, which during its execution gets represented as a HTML page and interpreted by the server.
WASH/CGI has something in that direction. I don't know a short introduction, but have a look at sections 4 and 8 of the implementation notes http://www.informatik.uni-freiburg.de/~thiemann/WASH/draft.pdf The basic idea is that displayForm in a CGI-script like main = do password <- displayForm $ (label "Enter password" <-> editbox) ... displays a HTML-page to the client, "waits" for a response and then resumes execution. It does not actually wait, but captures the continuation in the transmitted HTML page, for instance by saving a log of the previous events. This is related to [MonadPrompt], which has a similar purpose, and to [Unimo], which is pretty much the same but from the slightly different viewpoint of implementing any monad directly from its operational semantics. [Unimo]: Chuan-Kai Lin. Programming Monads Operationally with Unimo. http://web.cecs.pdx.edu/~cklin/papers/unimo-143.pdf [MonadPrompt]: Ryan Ingram. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/MonadPrompt Regards, apfelmus