DeltaStreams status (Re: [squeak-dev] Let's push it)

Göran Krampe goran at krampe.se
Tue Jun 30 16:59:03 UTC 2009


Hi!

Nicolas Cellier wrote:
> 2009/6/30 Göran Krampe <goran at krampe.se>:
>>> It's doable with user crafted pre/post scripts without system
>>> validation... Is that the solution?
>> You mean in Deltas? Well, a Delta is meant to be able to do everything a
>> Changeset can - so we need to support scripts (it is just another change
>> class called "DSDoit"). Since the changes are ordered the "doits" can appear
>> not only before or after but in the middle too :).
>>
>> So... well, I presume "surgery" gets a tad simpler to do with Deltas since
>> they simply record all the steps you perform. Thus, if you perform the steps
>> you describe above - in sequence - then you have a DSDelta that will work.
>> Slightly simpler than editing the Delta in order to add pre/post scripts
>> etc.
>>
>> This also means that we typically want to "prune" doits from Deltas, since
>> they are normally not really wanted.
>>
>> regards, Göran
> 
> Thanks, that's what I thought.
> I just wanted to point out that in some cases, special doIts are necessary.
> In theses cases, anti-delta generally won't work, and should better
> not be attempted.

I gully agree. :)

> OK for me if tools cover 90%, atomic loading is just another example
> not covering 100%.
> Just think of providing enough hooks for the remaining 10% in the
> overall process.
> This kind of refactoring will likely happen to anyone touching
> Process, Graphics, user interaction like Sensor, Compiler and other
> Kernel beasts... That's not that rare. Ask Igor, Andreas, Eliot,
> Michael, Marcus, etc...

I agree. This is actually one of the first inspirations of Deltas - I 
wanted a tool that could do relatively nice merging/conflict detection 
etc *without* advanced history. We all like the concreteness of 
ChangeSets - but we could still have a modern implementation. :)

In turn this was also inspired by git - not git itself, but by the 
philosophy of "let the tool be less smart and more predictable", it will 
still cover 80-90% and will be enough. And you get fewer surprises.

regards, Göran




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