use Perl

• Continuations (Score:2)

  by djberg96 (2603)

  ...continuation-based web frameworks

  Continuations are one of the things (among others, I'm told) that Ruby borrowed from Lisp. At least one framework, Borges [rubyforge.org], uses continuations as a way to deal with state.

  Unfortunately, I'm not one of those people smart enough to figure out how I can use continations to my advantage in daily work.
  • Re:Continuations (Score:1)

    by brev (1827) on 2004.07.05 13:57 (#32148)

    Almost every web app spends most of its time just recreating a state that it understands. And the logic of transitions between pages have to be unrolled into a big switch statement up front.

    If perl 7 had continuations, you could do this:

    #!/usr/bin/perl7
    
    # website that sells t-shirts
    
    $user = CGI::Continuation.new();
    
    show_start_page();
    
    if ($user.t_shirts) {
       show_shirts();  # each shirt has a buy button
       if ($user.show_close_up) {
           show_close_up($user.shirt_id);  # also shows buy button
       }
       if ($user.buy) {
           show_sizes();
           show_legal_stuff();
           show_credit_card_form();
           if ($user.credit_card.buy($user.shirt_id)) {
              show_thanks();
           } else {
              show_transaction_not_approved();
           }
       }
    }

    Continuation frameworks aren't a panacea--they run into trouble when dealing with world outside their interaction model. But you can see why they excite some people.

    N.B. it's not just about multi-page forms either. Check out Borges or Seaside for the details.

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