[ENH] EventEnhancement-nk

John W. Sarkela sarkela at sbcglobal.net
Wed Jun 18 15:20:43 UTC 2003


On Tuesday, June 17, 2003, at 04:30 PM, Andreas Raab wrote:

> Because of the above, I'm pretty certain you will have more discussions
> coming up about this in the future. Funny enough, the history of using
> events in Squeak is quite interesting in this regard:
> * first (I think) Stefan Matthias Aust wrote a first version - strong 
> refs
> * then I changed this - weak refs
> * then John's version went in - strong refs
> * then Rob changed it - weak refs
> So now it looks we'll go back to strong refs.

Very nearly almost, but not quite right. Stefan's version was the first 
incorporated by Squeak central into the image. There were earlier 
Squeak ports by others.

The real history of the mechanism follows.
* George Bosworth made some inventive changes to changed/update in 
Smalltalk/V.
* Steve Messick refined and designed the current form of events, 
introducing when:send:to;.
* The Dolphin guys (Blair and Andy) looked carefully at VSE and 
included events and exceptions VSE style and incorporated them into 
Dolphin Smalltalk. (A truly beautiful and well thought out product BTW.)
* I suspect Stefan got his ideas from the Dolphin port, in the process 
he missed the use of events as an information provider, the #needsXXX 
event pattern. He also missed the inherent sequencing of registrations.

The bulk of the credit for the version currently in VW and Squeak 
really belongs to Steve Messick. Probably one of the finest object 
designers I have ever known. All I did was write the smallest amount of 
code that passed the tests for the existence of Steve's design ideas.

>  I wonder for how long ;-)

How about as long as the simplest possible solution can work. I know 
that strong changed/update dependency has worked just fine for over two 
decades. :-}>

:-}> John Sarkela




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