[KCP] Thoughts on adding system changes and refactoring ChangeSet

Ned Konz ned at bike-nomad.com
Tue Jun 24 21:01:11 UTC 2003


On Tuesday 24 June 2003 01:17 pm, Andreas Raab wrote:
> If you insert a "safe notification mechanism" (such as notifying an
> intermediary object which later on notifies the interesting
> parties) then you have the problem of finding out when exactly "it
> is safe" to do so. Unless you have a theory about "the way the
> world works" (such as in Morphic: we're running complete cycles so
> after a completed cycle it's okay to do these kinds of things)
> you'd have to insert lots and lots of "extra notifications" (e.g.,
> "it's fine to do some other stuff now") in all of the calling
> processes which seems practically quite unfeasable.

We certainly don't want the UI in the middle of the compilation 
process.

I think Roel's concerns have to do with such things as UI tools like 
browsers and assistants. Similarly to what we have discussed about 
using some object to which we can delegate UI notifications like 
#inform: and #confirm:, we could have one or more objects that 
collects such notifications on compilation or other important events 
and then dispenses them to its subscribers when it's safe to do so.

So there could be one for the Morphic clients that would work 
synchronously with the world update cycle; perhaps another default 
one that would just discard the notifications, etc.

We already have at least one example of notification on such system 
events. Avi added (in PackageInfo) a notification from Utilities 
(#recentMethodSubmissions) that is triggered from 
Class>>noteCompilationOf:meta:. But it doesn't notice #doneCompiling, 
so it misses instVar changes, etc.

-- 
Ned Konz
http://bike-nomad.com
GPG key ID: BEEA7EFE



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