Comment by spacemanaki | Hacker News Reader

Comment by spacemanaki | Hacker News Reader

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As others have pointed out, chapters 4 and 5 are as wonderful and rich as they are because Scheme is homoiconic which makes writing Scheme interpreters and compilers in Scheme very easy -- no need for hairy lexing and parsing steps. Since (IMHO) these chapters are the best introduction to the study of programming languages and their implementation, it would be a real shame to discard them simply because JavaScript is more widely known and used than Scheme.

It's true that the ideas in the book transcend programming languages, and that the first 3 chapters could probably could be covered in JavaScript with little modification, if a little clumsily. But rewriting the 4th and 5th to include sections on parsing JavaScript would be quite challenging, and furthermore JavaScript does not have as simple semantics as Scheme, so there would be a loss of a great deal of elegance and beauty. The metacircular Scheme interpreter can run itself, which would be harder to do in JavaScript since its core is more rich and Scheme's core: objects, methods and so on complicate it quite a bit.

By the way, I read SICP and it's one of my favorite book. It's unbelievable how quick things are hacked... i.e. 2 pages and you've got a SQL-like language. Also, I must agree that Scheme really fit with the theme and the book. It's clean, it's concise, there's no funky syntax to learn. And, I also must agree that the interpreter and compiler parts would be much much more complex in JS.

All that being said, I still think lots of great concepts behind SICP can be explained with JS as the main language instead of scheme. If it can help some people to feel at home and quick the book, that's just great. They'll most likely like it and then read the real SICP for the other parts.

Lastly, I must agree that when I read SICP the first time, it was also to learn scheme as a side-effect. But it's not necessarily everyone.

and that metacircular evaluator is probably my favorite part of the (original) book right now...

"It's as if -- as if the key to the treasure is the treasure!"

i think the (new) book is valuable in that it might reach some people who have some mental block about just wanting to know what they "need" to know and think that all they need to know is javascript, but for those who just like learning? start scheming. it's freakin' awesome.

Not to mention that if you are already learning the concepts taught in SICP, then learning Scheme is trivial.

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