Lecture 7A: Metacircular Evaluator, Part 1

I re-watch this course every bunch of years, and every time I get something different from it. But mostly it just makes me happy - it's infectious and weird. Especially the "revelation" (spoiler!) ▶ this video

"We're getting really close to the spirit of the computer at this point, so I have to show a certain amount of reverence and respect" ▶ this video

I learned best in Scheme because you don't need to parse your input and can just evaluate a tree[0] (Parsing is, in my opinion, the most boring part about writing an interpreter!) Chapter 7 of Crafting Interpreters lays out how an evaluator works in a pretty clean way [1]. I've also blogged about evaluating ASTs in JavaScript [2] Lastly, Gary Bernhardt took it a step further and instead of "evaluating" code, "compiled" it to JavaScript (this tutorial uses Ruby) [3]. Very much a mind-blown moment for me. Have fun!! Writing interpreters remains one of my favorite things to do when learning a new programming language. [0] ▶ this video [1] link [2] link [3] link