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.
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