How to deal with changes in SmartRefStreams

Mark Guzdial guzdial at cc.gatech.edu
Tue Mar 30 16:01:33 UTC 1999


I've found that if you read any of the SqueakyPages on
http://minnow.cc.gatech.edu/squeakpages.1 with an updated Squeak 2.3, you
get loads of errors.  "UpdatingStringMorph has been changed" then
"ClockMorph" has been changed, then...  On most of them, simply clicking
the forward page button once gets you to the page you want, but not all of
them.  We're finding similar problems on our SqueakyPages + Swiki project
(MuSwiki). One of us playing with MuSwiki using an old image dragged
something onto the front page, now no one can read the front page in a
newer image without trying to invent a conversion method.

While I do understand that backward compatibility is a pink plane issue,
this is going to be a problem for those of us trying to use SqueakyPages
and the like in groups or in experiments, at least in the short term with
rapidly changing code bases.  Our current solution is to make sure that
everyone has the exact same image, but I'd like to find a more flexible
solution.  Some that I'm considering and would like comments on:

- Is there some kind of default behavior for SmartRefStream that we can
define so that there's an option NOT to provide a conversion method?

- What about setting up an update server of some kind that can provide
automatic conversion methods?  (It's certain that you already have a
network connection created if you're using MuSwikis or SqueakyPages that
have incompatible content :-)

- Can we shift the burden to the author, somehow?  "That object that you're
now adding has been changed since the last version.  Please provide a
conversion method for older images."  Or maybe to the developer of new
objects?

Thanks for any suggestions!
  Mark

--------------------------
Mark Guzdial : Georgia Tech : College of Computing : Atlanta, GA 30332-0280
(404) 894-5618 : Fax (404) 894-0673 : guzdial at cc.gatech.edu
http://www.cc.gatech.edu/gvu/people/Faculty/Mark.Guzdial.html





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