Re: [Axiom-developer] What is SubDomain (was: non extending category)
From:
Scott Morrison
Subject:
Re: [Axiom-developer] What is SubDomain (was: non extending category)
Date:
Tue, 14 Feb 2006 07:28:41 -0800
>> SCM: Do you happen to remember what you wrote 20 years ago? :)
Well, not really.
I do remember that I never liked SubDomain. We had all kinds of special-case code to deal with it, and it was only used for NonNegativeInteger and PositiveInteger. I believe the original motivation for sub-domains was to share implementations, but not categories. So PositiveInteger could share the all the implementation code from Integer, but not the categories of Integer, since they don't form a Group under addition, for example. In the end it caused a lot more mork than it saved.
The concept of sub-domain never made it into Aldor, as far as I know, and that's a good thing.