Make your own code formatter in Swift

on YouTube ↗31m

" summary

Team inconsistency motivates building a real formatter that actually rewrites code, not just enforces rules. It uses SwiftSyntax to parse a lossless AST and implements concrete edits like semicolon trimming, inserting numeric underscores, and turning nested if into guard. The proof is an open source formatter called swiftlylighter that applies these edits and runs on real code; it combines AST editing with lenses and prisms (optics) for deep traversal and notes some performance limits now but improvements land with newer Swift.

AI-written summary · about

" chapters (6)

1. 0:00Introduction
2. 1:21Coding Styles
3. 6:16Swift ASP Explore
4. 11:10Swift Formal Grammar
5. 20:28Optics
6. 26:46Composite optics

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