If you’ve gotten this far in the tutorial, then you’ll have built a Lexer and Parser for the Kaleidoscope programming language. If you haven’t read those, I’d strongly recommend reading Part 1 and Part 2 first. This time we’ll be turning this parser into a proper compiler by turning the parsed code into LLVM Intermediate Representation (LLVM IR).
In Part 1 of this tutorial, we built a lexer in Swift that can tokenize the Kaleidoscope language. Now we’re going to write a parser that can turn code from this language into an Abstract Syntax Tree, or AST.
Compilers are some of the most fascinating programs because they touch every aspect of Computer Science, from CLI and API design to calling conventions and platform-specific optimizations. Yet, many developers have a fearful reverence for them that makes them seem unapproachable. I think this is unnecessary.