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| author | elioat <elioat@tilde.institute> | 2023-08-23 07:52:19 -0400 |
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| committer | elioat <elioat@tilde.institute> | 2023-08-23 07:52:19 -0400 |
| commit | 562a9a52d599d9a05f871404050968a5fd282640 (patch) | |
| tree | 7d3305c1252c043bfe246ccc7deff0056aa6b5ab /js/games/nluqo.github.io/~bh/sicp.html | |
| parent | 5d012c6c011a9dedf7d0a098e456206244eb5a0f (diff) | |
| download | tour-562a9a52d599d9a05f871404050968a5fd282640.tar.gz | |
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diff --git a/js/games/nluqo.github.io/~bh/sicp.html b/js/games/nluqo.github.io/~bh/sicp.html new file mode 100644 index 0000000..94ed2d4 --- /dev/null +++ b/js/games/nluqo.github.io/~bh/sicp.html @@ -0,0 +1,128 @@ +<HTML> +<HEAD> +<TITLE>Why <cite>Structure and Interpretation of Computer Programs</cite> matters</TITLE> +</HEAD> +<BODY> +<H1>Why <cite>Structure and Interpretation of Computer Programs</cite> matters</H1> +<CITE>Brian Harvey<BR>University of California, Berkeley</CITE> + +<P>In 2011, to celebrate the 150th anniversary of MIT, the <i>Boston Globe</i> +made a list of the most important innovations developed there. They asked me +to explain the importance of <i>SICP,</i> and this is what I sent them: + +<P> + +<P>SICP was revolutionary in many different ways. Most importantly, it +dramatically raised the bar for the intellectual content of introductory +computer science. Before SICP, the first CS course was almost always +entirely filled with learning the details of some programming language. +SICP is about standing back from the details to learn big-picture ways +to think about the programming process. It focused attention on the +central idea of <i>abstraction</i> -- finding general patterns from specific +problems and building software tools that embody each pattern. It made +heavy use of the idea of <i>functions as data</i>, an idea that's hard to learn +initially, but immensely powerful once learned. (This is the same idea, +in a different form, that makes freshman calculus so notoriously hard even +for students who've done well in earlier math classes.) It fit into the +first CS course three different <i>programming paradigms</i> (functional, +object oriented, and declarative), when most other courses didn't even +really discuss even one paradigm. + +<P>Another revolution was the choice of Scheme as the programming language. +To this day, most introductions to computer science use whatever is the +"hot" language of the moment: from Pascal to C to C++ to Java to Python. +Scheme has never been widely used in industry, but it's the perfect +language for an introduction to CS. For one thing, it has a very simple, +uniform notation for everything. Other languages have one notation for +variable assignment, another notation for conditional execution, two or +three more for looping, and yet another for function calls. Courses that +teach those languages spend at least half their time just on learning the +notation. In my SICP-based course at Berkeley, we spend the first hour +on notation and that's all we need; for the rest of the semester we're +learning ideas, not syntax. Also, despite (or because of) its simplicity, +Scheme is a very versatile language, making it possible for us to examine +those three programming paradigms and, in particular, letting us see how +object oriented programming is implemented, so OOP languages don't seem +like magic to our students. Scheme is a dialect of Lisp, so it's great +at handling functions as data, but it's a stripped-down version compared +to the ones more commonly used for professional programming, with a +minimum of bells and whistles. It was very brave of Abelson and Sussman +to teach their introductory course in the best possible language <i>for +teaching</i>, paying no attention to complaints that all the jobs were in +some other language. Once you learned the big ideas, they thought, and +this is my experience also, learning another programming language isn't +a big deal; it's a chore for a weekend. I tell my students, "the language +in which you'll spend most of your working life hasn't been invented yet, +so we can't teach it to you. Instead we have to give you the skills you +need to learn new languages as they appear." + +<P>Finally, SICP was firmly optimistic about what a college freshman can be +expected to accomplish. SICP students write interpreters for programming +languages, ordinarily considered more appropriate for juniors or seniors. +The text itself isn't easy reading; it has none of the sidebars and colored +boxes and interesting pictures that typify the modern textbook aimed at +students with low attention spans. There are no redundant exercises; each +exercise teaches an important new idea. It uses big words. But it repays a +close reading; every sentence matters. + +<P>Statistically, SICP-based courses have been a small minority. But the book +has had an influence beyond that minority. It inspired a number of later +textbooks whose authors consciously tried to live up to SICP's standard. The +use of Scheme as a language for learners has been extended by others over a +range from middle school to graduate school. Even the more mainstream courses +have become sensitive to the idea of programming paradigms, although most of +them concentrate on object oriented programming. The idea that computer +science should be about ideas, not entirely about programming practice, has +since widened to include non-technical ideas about the context and social +implications of computing. + +<P>SICP itself has had a longevity that's very unusual for introductory CS +textbooks. Usually, a book lasts only as long as the language fad to which it +is attached. SICP has been going strong for over 25 years and shows no sign +of going out of print. Computing has changed enormously over that time, from +giant mainframe computers to personal computers to the Internet on cell +phones. And yet the big ideas behind these changes remain the same, and they +are well captured by SICP. + +<P>I've been teaching a SICP-based course since 1987. The course has changed +incrementally over that time; we've added sections on parallelism, concurrency +control, user interface design, and the client/server paradigm. But it's +still essentially the same course. Every five years or so, someone on the +faculty suggests that our first course should use language X instead; each +time, I say "when someone writes the best computer science book in the world +using language X, that'll be fine" and so far the faculty have always voted to +stay with the SICP course. We'll find out pretty soon whether the course can +survive my own retirement. + +<ul><li>(Footnote: Nope. Berkeley's new first course for majors uses Python, +with lecture notes that try to keep the ideas (and some of the text) of SICP.) +</ul> + +<P>The discussion has been sharper recently because MIT underwent a major +redesign of their lower division EECS curriculum. People outside MIT tend to +summarize that redesign as "MIT decided to switch to Python," but that's not a +perceptive description. What MIT decided was to move from a curriculum +organized around topics (programming paradigms, then circuits, then signal +processing, then architecture) to a curriculum organized around applications +(let's build and program a robot; let's build and program a cell phone). +<i>Everything</i> about their courses had to be reorganized; the choice of +programming language was the least of those decisions. Their new approach is +harder to teach; for one thing, each course requires a partnership of +Electrical Engineering faculty and Computer Science faculty. Perhaps in time +the applications-first approach will spark a revolution as profound as the one +that followed SICP, but it hasn't happened yet. + +<P>In my experience, relatively few students appreciate how much they're +learning in my course while they're in it. But in surveys of all our +CS students, it turns out to be among the most popular courses in +retrospect, and I regularly get visits and emails from long-gone students +to tell me about how they're using in their work ideas that they thought +were impractical ivory-tower notions as students. The invention of the +MapReduce software for data parallelism at Google, based on functional +programming ideas, has helped eliminate that ivory-tower reputation. + +<P><ADDRESS> +<A HREF="index.html"><CODE>www.cs.berkeley.edu/~bh</CODE></A> +</ADDRESS> +</BODY> +</HTML> |