Performance:
- Beware list-ref in a loop (O(n²) trap)
- Consolidated performance section with data structure selection rationale
- for/fold for single-pass result building
Parameters and dynamic scope:
- Good uses: ports, logging, config, test fixtures
- Bad uses: hidden global state, implicit argument passing
- Document when functions read from parameters
Also simplified Continuations section (parameterize now has its own section).
Major improvements:
- Iteration idioms: for/fold example, for*/list, in-naturals for indices
- Data structure mutability: when to use mutable hash/vector/box
- let/let*/define style: use let* when order matters
- Contracts section: when to use define/contract, ->i, boundary focus
- Naming: -ref/-set/-update suffixes for custom types
- Size heuristics: semantic ('one abstraction per module') not numeric
- Module hygiene: explicit provides only, contract-out when correctness matters
Removed:
- Packages/tooling section (covered in base racket.md injection)
Now 119 lines of actionable, non-obvious Racket guidance.
From docs.racket-lang.org/style, added only the non-obvious tips:
- Prefer define over let/let* (reduces indentation)
- Put provide before require (interface at top)
- Use racket/base for libraries (faster loading)
- Naming: prefix functions with data type (board-free-spaces)
- Use in-list/in-vector explicitly in for loops (performance)
- Use module+ test submodules with raco test
- Size limits: ~500 lines/module, ~66 lines/function
Skipped basic conventions LLMs already know (predicate suffixes, etc).
Racket-specific guidance for the carmack agent including:
- Idiomatic Racket patterns (match, for/*, cond)
- Module organization with explicit provide lists
- Contracts and type boundaries
- Data modeling with structs
- Error handling best practices
- IO, paths, and portability
- Performance considerations
- Macro guidelines
- Testing with rackunit
