I'm not conflating anything, as far as I'm aware. The question was: "the art of writing compilers and interpreters has effectively been lost" I'm curious, how

I'm not conflating anything, as far as I'm aware. The question was: "the art of writing compilers and interpreters has effectively been lost" I'm curious, how does that happen? Were the techniques used in compilers and interpreters of yore never recorded for posterity in academic papers or technical documentation? I think I did a pretty good job in answering it, although it was a bit rambling. The people on the standards committees for these languages are generally also the ones implementing compilers, at least at first. The ones that don't have significant overlap between the two fail. ALGOL-68 comes to mind in the past, FORTRAN-03/08 comes to mind now. Also, there were fast Lisp compilers back then (as fast as Lisp can get, at least, and keyword "compilers" as I'm not misinterpreting the two), along with decent (eh) Smalltalk compilers: Ruby isn't that unique. An optimizing compiler for Ruby could have used many of the techniques, given that most of the bottlenecks in Ruby are the same as many Lisps. Of course, it won't map perfectly, but much of it would. (I will admit that this paragraph is written with primarily old versions of Ruby in mind, because beyond 2007 or so, when it was basically a Lisp with Smalltalk tendencies under the hood, I haven't really kept up.) Many techniques absolutely have been lost over time, even in obvious spots, where you'd expect them to be maintained quite well; I have a folder of poorly-OCR'd, poorly-scanned ACM papers of novel, technically-interesting & fast pre-1990 compilers with significantly less downloads than citations. Academic papers aren't really where you'd expect to see "lost" techniques, but publishing is a wasteland, and most non-famous on this subject (and computers in general, partially; ever tried to find more than a handful of papers on Sun's Spring?) written between 1970 and 1990 are practically lost. The industry has the memory of a dormouse, though it might get better now that more and more things are becoming source-available.