Claude Sonnet 5.5 (effort default (no --effort flag) · thinking on) on Fix a spreadsheet formula engine (precedence, error values, static cycle detection, 5,000-cell chains without recursion errors)

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  "result": "I rewrote `sheet.py` to follow `SHEET_RULES.md`. I checked it only with a quick script of my own, not the hidden suite, and the checks I ran came out as expected.\n\n- **What I checked:**\n  - Precedence: `-2^2` gives 4, `2^3^2` gives 512, `2^-1` gives 0.5.\n  - Errors: `#DIV/0!`, `#NAME?`, `#ERROR!`, `#VALUE!` and `#CYCLE!` all came out correctly. `#CYCLE!` was only tested on a range that includes its own cell.\n  - Behaviour: `IF` skips the branch it doesn't take, and the aggregate functions ignore empty and text cells.\n  - Size: a 5,000-cell dependency chain evaluates in about 0.03 s with no `RecursionError`.\n- **How it works:**\n  - A tokenizer and recursive-descent parser build a syntax tree, so no `eval` or `exec` is used. Only the standard library is imported.\n  - Cycles are found with an iterative Tarjan pass, which also gives the order to evaluate cells in, so long chains never recurse.\n  - The command-line wrapper `python3 sheet.py in.csv out.csv` still works. I haven't run it on a real CSV.\n- **Judgment calls on unspecified cases:**\n  - An unknown function gives `#NAME?` even if its arguments hold errors.\n  - A range inside an unknown function is a syntax error.\n  - `(A1)` counts as a single reference in aggregates.\n  - A cell with a syntax error adds no dependency edges, so it can't be part of a cycle.\n  - Overflow in `^` returns `inf`.\n  - A negative base with a fractional exponent gives `#VALUE!`.",
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