Taming the Flat AST: Ergonomics in the Age of Zero Allocations Last week, I introduced egg , a modern LL(1) parser generator for Go. The response from the community was insightful, particularly regarding egg 's most distinct feature: the flat AST. To achieve high performance and low garbage collection pressure, egg encodes the entire Abstract Syntax Tree (AST) into a single []int32 slice. While this is excellent for the CPU cache, it can be intimidating for the developer. One commenter on the Gophers Slack put it perfectly: "The 'Traversing the AST' section really dissuades me from using this tool... I think coming up with a clean, well-typed API might be harder than I think." They were right. In my previous post, I showed a raw recursive walker that involved manual index arithmetic. It was fast, but it wasn't pretty. However, shortly after that post, I implemented ImportEBNF —a feature allowing egg to bootstrap itself by reading EBNF from ...