From: Alexey Petrushin <axyd80@...>
Date: 2008-04-16T21:41:17+09:00
Subject: Continuation in web (Seaside clone)

Hello!

IN SHORT (by some example):

There is a web application, and two 'pages' - 'View' and 'Editor'. And
when i press 'Edit' button on the 'View' it should:
- Freeze current execution (callcc {bla-bla})
- Give control to 'Editor'
- User fill data in 'Editor'
- 'Editor' return entered data and control back to 'List'
(continuation.call data)
- Friezed execution resumes

THE PROBLEM:
I implement this the same way as in Seaside, and it seems to should
works, but it throws:
"Caught RuntimeError: continuation called across threads"

Probably, because WebServer runs each request in a new thread. Do you
hawe any idea how this can be solved?

Thanks!

DETAILS:
In pseudo code:

class Editor < Form
  def initialize
    data = TextField.new self, ''
    FormButton.new(self, 'Save') {answer data.text}
    end
end

class View < Panel
  def initialize editor
    view= Label.new self, 'Some initial value ...'
    Button.new(self, 'Edit') {view.text = call(editor)}
    end
end

class MySuperApp < Panel
  def initialize
    View.new(self, Editor.new)
    end
end
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