> especially hard for beginner students Perhaps you don't know that 50 years ago Smalltalk was being taught to middle school and high school students? > Nothi

> especially hard for beginner students Perhaps you don't know that 50 years ago Smalltalk was being taught to middle school and high school students? > Nothing so simple exists in smalltalk Have you actually used Smalltalk? ---- `I will always remember a debug emergency call I received during one of our student classes. A girl was experimenting with numbers in Smalltalk-80, and suddenly her system froze when she tried to reframe a window. Although the UI was unresponsive, the "emergency evaluator" window was still operating so I was able to take a look at what had happened. Her window was trying to display itself, but was encountering an error because BitBlt, responsible for painting the border, had a width that was. . . wait a minute. . . a Fraction? We did not even have fractions in the student system, but she said, "Oh yes, I added a Fraction class". Interestingly, BitBlt was written to be resilient, in that if it received a non-integer argument, it would call itself again after sending the message asInteger to that argument. However, her fractions did not have such a method, so the debugger had stopped at that point and was not even able to show the problem because of another such infraction (er, sorry). I asked whether she had a conversion to integer and she replied no, but that her fractions did have a makeFloat message. We talked about the problem, and I got her to suggest defining Fraction understands: 'asInteger' as: '↑ self makeFloat asInteger' We were able to type this into the emergency evaluator, at which point the debugger miraculously displayed itself, the window she had tried to reframe reappeared, and everything in the system seemed to work again. Probably hundreds of methods in the system were now operating just fine with rectangles whose coordinates were instances of a student’s newly defined Fraction class. This illustrates the astounding ability of message-sending systems to absorb unanticipated constructions.` Daniel Ingalls "The Evolution of Smalltalk" 85:63 Proc. ACM Program. Lang., Vol. 4, No. HOPL, Article 85. Publication date: June 2020 https://dl.acm.org/doi/pdf/10.1145/3386335 https://dl.acm.org/doi/pdf/10.1145/3386335