Lecture 1A: Overview and Introduction to Lisp

It’s funny you should ask that as I was just watching a lecture by Harold Abelson in which he addresses this exact question. this video In case you don’t have the time or inclination to watch the video it can basically be summarized by saying the following. When the Egyptians first discovered geometry it was considered crop science as it’s primary application was for determining crop yields and when to plant and harvest. In the same way now that computers science is applied to computers today. But just like Geometry is really about farming, computer science is not really about computers. Professor Abelson goes on to explain that computer science provides a means to determine proofs for abstract mathematics a reasoning, so that we can understand with definitive proof things that until now were only theoretical.

Don't know if the "joke" originated with Abelson and Sussman but here's Hal Abelson talking about it: this video "It's not about computers in the same sense that physics is not really about particle accelerators." I sort of agree, but I guess it depends on what we mean about computer science being about computers. We can do things now that were downright impossible when A&S recorded their Lisp lectures simply because we can think differently about what's reasonable with regards to time and space complexity. And, of course, Abelson himself jokes about everyone wanting a faster computer in a later lecture. Perhaps we're simply confusing CS with software development, which I suppose could be likened to confusing mathematics with accounting.

The beginning of this lecture (30 seconds in) by Harold Abelson (author of SICP - Structure and Interpretation of Computer Programs) explains why Computer Science is a terrible name here. this video Not sure about the year.

> Turing Machines, on the other hand, were instantly obviously mechanizable. It was clear that one could build a physical machine to run any Turing program without human input. Harold Abelson points out in one of his lectures [0] that computer science isn't about computers any more than biology is about microscopes. From that perspective, it is clear that Turing found an existing discipline of computer science and made major contributions to it. But it doesn't really seem right to say that he invented or founded computer science. [0] this video

> Written for freshman at MIT, it is ostensibly an entry-level text. But it requires such a level of competence in math and physics, and the prose itself is so dense and archaic, that I couldn't imagine suggesting it to anyone. It’s also a complement to a course, the implications here being that chapters and examples are to be discussed in class and that a certain amount of lab-work has to be performed as well for the concepts to sink-in. But It’s not for everyone. I couldn’t see a bootcamp based on this book for instance. It does assume a fair bit of math and physics knowledge (or a curiosity for such) because it was written with engineering students in mind who, for some of them, were encountering a computer for the first time of their lives. [0] > One guess is intelligence signalling. That it is human nature for a person to suggest a book in an attempt make herself look smart rather than to best assist the person asking for a suggestion. This is clickbait. SICP has been used for decades and is extremely well regarded as an introductory book. Maybe the OP lacked the fundamentals required for approaching it. If the authos has a CS degree, that reflects poorly on the program he completed. > If you love challenging books, you are neither the norm nor the audience of this post. But the MIT freshman this book was written for definitely are. [0] this video

Actual PDF from MIT: (I assume they’re happy to let anyone use it) link There’s the set of the 1986 lectures on MIT’s Open CourseWare: this video

>Maintaining tree on text editors requires careful editing and strict practices, which human brains aren't good at. The "tree" will get broken at some point, but, in this school of thought, the recovery strategy is unclear and inconsistent at best. We've had editors that automatically do that since the 70s. Here's a live demo hot from 1986: this video >The real tree, at the end of the day, is formed by line breaks and indents, not parenthesis. It isn't. You're not the type of person who lisp is for, which is fine. There are lots of languages suited for people like you. But I'd be curious to know what language you think uses nothing but line breaks and indents to describe its AST.

> Here's a live demo hot from 1986: this video The process in the video still perfectly aligns with my description. Actually, I reached that conclusion by observing people writing Lisp code. That is, when you're writing Lisp code, that's exactly what people next you would see, no matter what you think. Also, trailing ")"s are clearly a burden, as people do spend their brain cycles to properly match them. > It isn't. You're not the type of person who lisp is for You sound like you're right in the middle of Lisp fever, which is fine. Everyone goes through that. > But I'd be curious to know what language you think uses nothing but line breaks and indents to describe its AST. You simply didn't get what I was saying. Even when all the parens were stripped off from a Lisp code, you can easily reinsert parens based on line breaks and indents. So people rely more on indentations for correctly putting parens, rather than being cautions w/ every single editing operation.

As Hal Abelson said back in 1986 in the original SICP lectures [1] while drawing `(+ 3 (* 5 6) 8 2)` and the corresponding syntax tree on the board: >"We're writing these trees ... and parentheses are just a way to write this two dimensional structure as a linear character string. Of course, when LISP first started and people had teletypes or punchcards or whatever and (the parentheses character structure) was more convinient. But maybe if LISP started today the syntax would look more like (a 2D syntax tree)." [1]: this video