Temperature subtype is a poor example to apply OOP. Try modeling a thermometer or a thermostat.
Then simply extend it for several ways to message its data to other objects, such as the textual user interface Transcript, a GUI widget, or a log file, or the internet of things. (Epiphany begins here.) There is a Lisp interpreter in Gnu Smalltalk (gst). Play with its examples. There is a Prolog interpreter in gst. Play with its examples. Gst has a few versions of Tetris. Examine the smallest Tetris example and see how it was extended for multiple GUI’s. You can also try Squeak for a highly developed playground. Lastly, GnuStep API uses Objective C, and offers a Smalltalk interpreter for scripting called StepTalk. Also, apps can be written in Objective C++. (But StepTalk is not high-performance like gst with Lightning JIT, or Squeak with Open Smalltalk VMs.) -- John On Jan 6, 2026, at 5:10 PM, Duke Normandin <[email protected]> wrote: ... [SNIP] ... I've been hacking code since 1981 or so - never using OOP - but using Perl, C, PHP, various Lisps & Schemes. The Smalltalk code I wrote was intended to created a function/method that could be called in order to return a temperature using a particular scale. I was not interested in what "universe" the "object" lived in that I needed the temperature for. Just like I the `abs' function doesn't care what its given argument pertains to. `abs' is simply a built-in function, or one living it a "math" library/module/package. ... Maybe it's just the Smalltalk syntax that is getting in my way. I'm going to try some other OOP supported language to see if the whole process becomes more intuitive for me. ...
