https://www.coldfix.eu/2015/05/16/bison-c++11/
https://www.geeksforgeeks.org/flex-fast-lexical-analyzer-generator/
http://anoopsarkar.github.io/compilers-class/yacc-practice.html
vid calculator written with flex/bison
https://nullprogram.com/blog/2019/01/25/
books
courses
Clang Tooling I (add override keyword) https://medium.com/@chichunchen844/clang-tooling-i-add-override-keyword-ddfdf6113b24