Why do ChangeSets sort?

Ned Konz ned at bike-nomad.com
Wed Feb 19 18:11:55 UTC 2003

On Tuesday 18 February 2003 09:34 pm, Richard A. O'Keefe wrote:
> I would consider separating the installation into several change
> sets all stuck in a SAR. You can then load them in the proper
> order, and/or have conditional loading based on Squeak versions.
> Is SAR available for Squeak 3.0?

I don't know. I suspect it would work, but haven't tried it. I'd try 
the SARInstaller for 3.2 package.

> (Documentation problem:  my network connection is down again.
>  IT services are getting ready for the beginning of semester, and
>  this seems to make my off-campus Web access disappear from time to
> time.) Having a whole bunch of change-sets just to get things done
> in the order I did them seems a little, no, extremely unfriendly of
> Squeak.
> 	> Q4:  I'd like the change set to be usable in 3.0, 3.2, and 3.4.
> 	>      Is it OK if a change set file contains directives to remove
> 	> methods that don't exist?  How do I make one remove a method
> 	> from a _class_ that might not exist in some version?
> 	I'd stick this in a preamble or postscript, generally, or in a
> 	separate change set for that specific version.

> Details, please.  I know what preambles and postscripts are and how
> to create them, but WHAT do I stick in there?  What MAY I stick in
> there?

The preambles and postscripts of *change sets* are just Squeak code 
that gets executed. You can put pretty much anything in them.

So you could have code like:

(Smalltalk includesKey: #SomeClass) ifTrue: [ ... do something to 
SomeClass ].


(Smalltalk version beginsWith: 'Squeak3.0') ifTrue: [ ... something 
for 3.0 ... ]

In the SAR preamble and postscript (install/preamble and 
install/postscript), the same is true, with the addition that "self" 
represents the SAR Installer itself.

The SAR Installer has methods like:

extractMember: name


fileInMemberNamed: name

that take SAR member files and extract them to files or file them in 
as change sets or .st files.

So putting this together, you can do the entire installation in the 

(Smalltalk version beginsWith: 'Squeak3.0') ifTrue: [ 
	self fileInMemberNamed: 'MyStuffFor3.0.cs' ].


> If Squeak can't remember what order I did things in, letting me
> explicitly tie the changes into some sort of order and remembering
> _that_ might be a good idea.

Ned Konz

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