SICP is fundamentally about the notion that programs are primarily a means of communication between people, being written by people for other people to read, an

SICP is fundamentally about the notion that programs are primarily a means of communication between people, being written by people for other people to read, and only secondarily a thing for computers to execute. And it really opened my eyes to the landscape of programming paradigms that exist—indeed, it continues to do so! But your comment is completely off-base. In Circuits and Electronics, as I understand it, the "structures" being discussed are circuit schematics, things like this keyboard I designed last month https://tinyurl.com/23tdsm4c https://tinyurl.com/23tdsm4c. While SICP does talk about circuit schematics, I don't think anyone would claim that S-expressions are a reasonable alternative way for people to read and write such things. You're completely confused about Signals and Systems, because you said "functionality", a word which refers to the kind of "functional" a machine might be. In that context, saying that something is "functional" means that it works. But the "functional" that describes Signals and Systems is the mathematical idea of a "function", which is a not-necessarily-computable relation of each possible input to one (possibly not distinct) output. The kinds of "functions" we're talking in S&S are the kinds of functions where you can take the Laplace transform or plot the frequency and phase response. It isn't about functionality at all! While S-expressions are perfectly capable of expressing ideas like these, and indeed SICM investigates those possibilities in much more detail, SICM hadn't been written yet, and SICP and 6.001 touch on them only briefly. Following SICM I think even its authors were doubtful about whether Scheme was a good medium for working with those ideas. I don't know anything about Computation Structures, so I can't really say anything about it. Maybe you're right that it would fit perfectly well into 6.001. Apparently it survived the purge; https://ocw.mit.edu/courses/6-004-computation-structures-spring-2017/ https://ocw.mit.edu/courses/6-004-computation-structures-spr... says: > This course introduces architecture of digital systems, emphasizing structural principles common to a wide range of technologies. It covers the topics including multilevel implementation strategies, definition of new primitives (e.g., gates, instructions, procedures, processes) and their mechanization using lower-level elements. It also includes analysis of potential concurrency, precedence constraints and performance measures, pipelined and multidimensional systems, instruction set design issues and architectural support for contemporary software structures.