More on Change Sets and Maintenance

Date: Thu, 28 Aug 1997 22:19:45 -0500 (CDT)
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To: (Mark Guzdial)
From: (Ralph E. Johnson)
Subject: Re: novice information

>What's the best way to proceed with questions? Do you think that I should >just send them to you, or shall I post them to the Squeak mailing list?

It is fine to send them to the Squeak mailing list unless you are sending one a day. People might get annoyed if they see one every day. I doubt if you will do that.

>The most significant benefit compared to filing out categories seems to be >recording changes to base system classes. How often do you find that you >need to do that, in general? I would imagine that it depends alot on what >you're doing with Smalltalk. For application-level programming, it would >be pretty rare that you would change a base class, isn't it?

It is actually fairly common. For example, it is common to add methods to Object because you want every object to speak a new protocol, and you give Object a default implementation. Changing system methods is dangerous, but adding methods to system classes is safe.

>What's the ChangeSet Sorter for? I haven't found a description of it in >the Orange book, yet.

It is different from the original Smalltalk-80 tool, and I haven't used it yet. The general idea is to edit a change set.

>What does it mean to "build a new image"? Start from a base image and >fileIn all your change sets and file outs?


>Does "file out all changes" respect change set boundaries (i.e., which >project I'm in), or does it file out everything in the changes file?


>Agreed! I've heard people talk about ENVY but don't know much about it. I >assume that it's a kind of revision control system?

ENVY helps you break your system into "applications", which are groups of classes. It manages multiple versions of applications, and also new applications that are extensions of old ones. It is a revision control system, and also a general configuration management tool.


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