DeltaStreams small update

Klaus D. Witzel klaus.witzel at
Thu Aug 23 12:46:44 UTC 2007

Hi Göran,

I refer to your proposed Delta File Format, with your remarks Human  
readable? encoding , (utf8? BOM or no BOM?) (put encoding in header?) and  
the Method Source preamble.

Can I suggest to consider a small XML-parseable format, which is so flat  
that it is easy to parse by just the two methods #upTo: and #scanTokens:  
(perhaps assisted by #replaceAll: $" with: $' and #utf8ToIso).

This way Deltas could perfectly be used in other markedup docs, for  
example with xhtml. Also transport (http+friends) and transfer encoding  
can be handled by existing (hope so :) protocols. It would look like

<?xml version="1.0" encoding="UTF-8"?><...  
<st:class name="SuperDeltaObject" superclass="Object" dialect="Squeak">
  <st:classcomment /> <!--uhm, what class comment ;-) -->
  <st:method selector="with:do:" category="--all--" timestamp="8/23/2004  
14:41" author="st">
with: this do: that
  ^ this perform: that
  <st:metaclass instvars="">
   <st:method selector="initialize" category="class initialization"  
timestamp="8/23/2004 14:42" author="st">

All the not explicitly mentioned attributes can have an intuitive default  
(like format="fixed" and instvars="", etc) and complex attributes (like  
oldinstvarorder="c b a") can be ignored by simple readers.

It looks a bit wordy but, what do you think?


On Tue, 21 Aug 2007 03:01:45 +0200, <goran at> wrote:

> Hi all!
> Ok, managed to get some more code written tonight - but I am still on a
> low level here - matching up with ChangeSet etc. But if anyone wants to
> join in:
> 	See details here:
> The first goal is to make DSDelta work as a "true log" capturing all
> changes in full detail.
> One question for you gurus out there - do we care about changing the
> ORDER of say instvars?
> regards, Göran

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