For some time I've been looking for an opportunity to do a stream on writing a parser + interpreter for... something. Anything really. I've wanted to implement a parser following matklad's excellent article on Pratt parsing ( https://matklad.github.io/2020/04/13/simple-but-powerful-pratt-parsing.html ), though honestly anything in the area of parsing would do. Well, CodeCrafters have recently released a new challenge in beta that follows Robert Nystrom's Crafting Interpreters book ( https://craftinginterpreters.com/ ), so I jumped at the opportunity. Join me in working through the challenges, or try it yourself first and compare notes after the fact!
You can access the challenge over at https://app.codecrafters.io/join/interpreter?via=jonhoo , which also gives you 7 days free access, or in free source form (without the nice infrastructure) at https://github.com/codecrafters-io/build-your-own-interpreter .
You can find my solution code over at https://github.com/jonhoo/lox
You can join my Discord at https://discord.jonhoo.eu/
0:00:00 Introduction
0:07:36 What is compilation?
0:28:54 The Lox language
0:44:26 Lexing single-character tokens
1:40:31 Lexing multi-character tokens
2:14:18 Lexing numbers
2:47:54 Lexer errors
3:05:37 Lexing comments
3:15:53 Lexing strings
3:29:13 Printing numbers
3:36:09 Outlining the (Pratt) parser
4:16:41 Parsing expressions
5:01:18 Parsing special statements
5:58:56 Extract out statement parser
6:38:42 Finish up expression parser
6:49:34 Printing token trees
6:59:47 Trying out the parser
7:29:13 Aligning with expected output
7:37:02 Tests falling like dominoes
7:50:41 Outro
Live version with chat: https://youtube.com/live/FdZmJ0DAmn4